diff --git a/.env.backup b/.env.backup
index e98b62c..04f5047 100644
--- a/.env.backup
+++ b/.env.backup
@@ -31,3 +31,9 @@ JWT_EXPIRE_MINUTES=1440
 # 应用配置
 APP_ENV=development
 LOG_LEVEL=INFO
+
+# PayPal 支付配置（Sandbox 测试环境）
+PAYPAL_CLIENT_ID=AWJcBVeccSgDDhcZcYEbf4SJKxq9Uk_qVNlvk9mCewzl9o1Cp0onPzOD-v26-Mye9F1cKF6SzipuTtQZ
+PAYPAL_CLIENT_SECRET=EJVeShfyCCTLvNejkhs6F943gYfNyNFkbmw-CFOA0VEGLsiqic0GPthYzVQLBajzH-v8PVpJ0SM51ccL
+PAYPAL_ENVIRONMENT=sandbox
+PAYPAL_WEBHOOK_ID=
diff --git a/docker-compose.yml b/docker-compose.yml
index ac3dfc7..556593f 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -72,6 +72,11 @@ services:
       - SMTP_PORT=${SMTP_PORT:-465}
       - SMTP_EMAIL=${SMTP_EMAIL:-taijiagent@189.cn}
       - SMTP_PASSWORD=${SMTP_PASSWORD:-eR)8hD@1Q)3sU%2q}
+      # PayPal 支付配置
+      - PAYPAL_CLIENT_ID=${PAYPAL_CLIENT_ID:-AWJcBVeccSgDDhcZcYEbf4SJKxq9Uk_qVNlvk9mCewzl9o1Cp0onPzOD-v26-Mye9F1cKF6SzipuTtQZ}
+      - PAYPAL_CLIENT_SECRET=${PAYPAL_CLIENT_SECRET:-EJVeShfyCCTLvNejkhs6F943gYfNyNFkbmw-CFOA0VEGLsiqic0GPthYzVQLBajzH-v8PVpJ0SM51ccL}
+      - PAYPAL_ENVIRONMENT=${PAYPAL_ENVIRONMENT:-sandbox}
+      - PAYPAL_WEBHOOK_ID=${PAYPAL_WEBHOOK_ID:-2W328200AC5518345}
     extra_hosts:
       - "host.docker.internal:host-gateway"
     volumes:
diff --git a/plans/PayPal支付集成-后端实施文档.md b/plans/PayPal支付集成-后端实施文档.md
index 23f2984..e234e6b 100644
--- a/plans/PayPal支付集成-后端实施文档.md
+++ b/plans/PayPal支付集成-后端实施文档.md
@@ -1278,12 +1278,12 @@ logs = await query_audit_logs(
 
 ## 9. 任务清单
 
-- [ ] 安装 `paypal-server-sdk` 依赖
-- [ ] 添加 PayPal 配置到 `config.py`
-- [ ] 在 `app/audit.py` 添加 PayPal 审计操作类型
-- [ ] 创建 `app/paypal_client.py` 客户端封装
-- [ ] 创建 `app/routes/paypal.py` 路由（含审计日志）
-- [ ] 在 `main.py` 注册路由
-- [ ] 添加环境变量配置
+- [x] 安装 `paypal-server-sdk` 依赖
+- [x] 添加 PayPal 配置到 `config.py`
+- [x] 在 `app/audit.py` 添加 PayPal 审计操作类型
+- [x] 创建 `app/paypal_client.py` 客户端封装
+- [x] 创建 `app/routes/paypal.py` 路由（含审计日志）
+- [x] 在 `app/routes/__init__.py` 注册路由
+- [x] 添加环境变量配置
 - [ ] 编写单元测试
 - [ ] 配置 PayPal Webhook
\ No newline at end of file
diff --git a/scripts/https_proxy.py b/scripts/https_proxy.py
new file mode 100644
index 0000000..084ceb5
--- /dev/null
+++ b/scripts/https_proxy.py
@@ -0,0 +1,147 @@
+#!/usr/bin/env python3
+"""
+HTTPS 代理服务器
+用于测试环境，将 HTTPS 请求转发到本地 HTTP 服务
+
+使用方法:
+    python3 https_proxy.py --port 8989 --target http://localhost:8000 \
+        --cert ssl_certs/cert.pem --key ssl_certs/key.pem
+"""
+
+import argparse
+import ssl
+import http.server
+import urllib.request
+import urllib.error
+import socketserver
+import json
+from urllib.parse import urlparse
+
+
+class ProxyHandler(http.server.BaseHTTPRequestHandler):
+    """HTTPS 到 HTTP 代理处理器"""
+    
+    target_url = "http://localhost:8000"
+    
+    def do_request(self, method: str):
+        """处理所有 HTTP 方法"""
+        # 构建目标 URL
+        target = f"{self.target_url}{self.path}"
+        
+        # 读取请求体
+        content_length = int(self.headers.get('Content-Length', 0))
+        body = self.rfile.read(content_length) if content_length > 0 else None
+        
+        # 构建请求头（转发原始头）
+        headers = {}
+        for key, value in self.headers.items():
+            # 跳过 hop-by-hop 头
+            if key.lower() not in ('host', 'connection', 'keep-alive', 
+                                   'transfer-encoding', 'te', 'trailer',
+                                   'proxy-authorization', 'proxy-authenticate',
+                                   'upgrade'):
+                headers[key] = value
+        
+        # 添加 X-Forwarded 头
+        headers['X-Forwarded-For'] = self.client_address[0]
+        headers['X-Forwarded-Proto'] = 'https'
+        
+        try:
+            # 创建请求
+            req = urllib.request.Request(
+                target,
+                data=body,
+                headers=headers,
+                method=method
+            )
+            
+            # 发送请求
+            with urllib.request.urlopen(req, timeout=30) as response:
+                # 发送响应状态
+                self.send_response(response.status)
+                
+                # 转发响应头
+                for key, value in response.headers.items():
+                    if key.lower() not in ('transfer-encoding', 'connection'):
+                        self.send_header(key, value)
+                self.end_headers()
+                
+                # 转发响应体
+                self.wfile.write(response.read())
+                
+        except urllib.error.HTTPError as e:
+            self.send_response(e.code)
+            for key, value in e.headers.items():
+                if key.lower() not in ('transfer-encoding', 'connection'):
+                    self.send_header(key, value)
+            self.end_headers()
+            self.wfile.write(e.read())
+            
+        except urllib.error.URLError as e:
+            self.send_error(502, f"Bad Gateway: {e.reason}")
+            
+        except Exception as e:
+            self.send_error(500, f"Internal Server Error: {str(e)}")
+    
+    def do_GET(self):
+        self.do_request('GET')
+    
+    def do_POST(self):
+        self.do_request('POST')
+    
+    def do_PUT(self):
+        self.do_request('PUT')
+    
+    def do_DELETE(self):
+        self.do_request('DELETE')
+    
+    def do_PATCH(self):
+        self.do_request('PATCH')
+    
+    def do_OPTIONS(self):
+        self.do_request('OPTIONS')
+    
+    def log_message(self, format, *args):
+        """自定义日志格式"""
+        print(f"[HTTPS Proxy] {self.client_address[0]} - {format % args}")
+
+
+class ThreadedHTTPServer(socketserver.ThreadingMixIn, http.server.HTTPServer):
+    """支持多线程的 HTTP 服务器"""
+    daemon_threads = True
+
+
+def main():
+    parser = argparse.ArgumentParser(description='HTTPS to HTTP Proxy Server')
+    parser.add_argument('--port', type=int, default=8989, help='HTTPS port to listen on')
+    parser.add_argument('--target', default='http://localhost:8000', help='Target HTTP URL')
+    parser.add_argument('--cert', required=True, help='SSL certificate file')
+    parser.add_argument('--key', required=True, help='SSL private key file')
+    
+    args = parser.parse_args()
+    
+    # 设置目标 URL
+    ProxyHandler.target_url = args.target.rstrip('/')
+    
+    # 创建 SSL 上下文
+    ssl_context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
+    ssl_context.load_cert_chain(args.cert, args.key)
+    
+    # 创建服务器
+    server = ThreadedHTTPServer(('0.0.0.0', args.port), ProxyHandler)
+    server.socket = ssl_context.wrap_socket(server.socket, server_side=True)
+    
+    print(f"HTTPS Proxy Server started on port {args.port}")
+    print(f"Forwarding to: {args.target}")
+    print(f"Press Ctrl+C to stop")
+    print()
+    
+    try:
+        server.serve_forever()
+    except KeyboardInterrupt:
+        print("\nShutting down...")
+        server.shutdown()
+
+
+if __name__ == '__main__':
+    main()
diff --git a/scripts/start_https_proxy.sh b/scripts/start_https_proxy.sh
new file mode 100755
index 0000000..87acdc4
--- /dev/null
+++ b/scripts/start_https_proxy.sh
@@ -0,0 +1,40 @@
+#!/bin/bash
+# PayPal Webhook HTTPS 代理启动脚本
+# 用于测试环境，将 HTTPS 请求转发到本地 HTTP 服务
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+CERT_DIR="$SCRIPT_DIR/ssl_certs"
+HTTPS_PORT=8989
+HTTP_TARGET="http://localhost:8000"
+
+# 创建证书目录
+mkdir -p "$CERT_DIR"
+
+# 生成自签名证书（如果不存在）
+if [ ! -f "$CERT_DIR/cert.pem" ] || [ ! -f "$CERT_DIR/key.pem" ]; then
+    echo "生成自签名 SSL 证书..."
+    openssl req -x509 -newkey rsa:4096 -keyout "$CERT_DIR/key.pem" -out "$CERT_DIR/cert.pem" \
+        -days 365 -nodes -subj "/CN=localhost" 2>/dev/null
+    echo "证书已生成: $CERT_DIR/"
+fi
+
+echo ""
+echo "=========================================="
+echo "PayPal Webhook HTTPS 代理"
+echo "=========================================="
+echo "HTTPS 端口: $HTTPS_PORT"
+echo "转发目标: $HTTP_TARGET"
+echo ""
+echo "PayPal Webhook URL 配置为:"
+echo "  https://your-public-ip:$HTTPS_PORT/whitelist/payment/callback/paypal"
+echo ""
+echo "注意: 自签名证书仅用于测试，PayPal Sandbox 可能不接受"
+echo "生产环境请使用有效的 SSL 证书"
+echo "=========================================="
+echo ""
+
+# 启动 Python HTTPS 代理
+python3 "$SCRIPT_DIR/https_proxy.py" --port $HTTPS_PORT --target "$HTTP_TARGET" \
+    --cert "$CERT_DIR/cert.pem" --key "$CERT_DIR/key.pem"
diff --git a/scripts/start_ngrok_tunnel.sh b/scripts/start_ngrok_tunnel.sh
new file mode 100755
index 0000000..803684e
--- /dev/null
+++ b/scripts/start_ngrok_tunnel.sh
@@ -0,0 +1,38 @@
+#!/bin/bash
+# PayPal Webhook 测试 - 使用 ngrok 创建 HTTPS 隧道
+#
+# 使用方法:
+#   1. 首次使用需要注册 ngrok 账号并配置 authtoken:
+#      ngrok config add-authtoken <your-authtoken>
+#
+#   2. 运行此脚本:
+#      ./scripts/start_ngrok_tunnel.sh
+#
+#   3. 复制 ngrok 生成的 HTTPS URL，在 PayPal Developer Dashboard 配置 Webhook:
+#      https://xxxx.ngrok-free.app/whitelist/payment/callback/paypal
+
+set -e
+
+# MCP Server 端口（Docker 映射端口为 8002）
+MCP_PORT=${MCP_PORT:-8002}
+
+echo ""
+echo "=========================================="
+echo "PayPal Webhook 测试 - ngrok HTTPS 隧道"
+echo "=========================================="
+echo ""
+echo "正在为本地端口 $MCP_PORT 创建 HTTPS 隧道..."
+echo ""
+echo "启动后，请在 PayPal Developer Dashboard 配置 Webhook URL:"
+echo "  https://<ngrok-url>/whitelist/payment/callback/paypal"
+echo ""
+echo "选择以下事件类型:"
+echo "  - PAYMENT.CAPTURE.COMPLETED"
+echo "  - PAYMENT.CAPTURE.DENIED"
+echo "  - PAYMENT.CAPTURE.REFUNDED"
+echo ""
+echo "=========================================="
+echo ""
+
+# 启动 ngrok
+ngrok http $MCP_PORT
diff --git a/services/mcp-server/app/audit.py b/services/mcp-server/app/audit.py
index 046f5ce..72f15b2 100644
--- a/services/mcp-server/app/audit.py
+++ b/services/mcp-server/app/audit.py
@@ -56,6 +56,13 @@ AUDIT_ACTIONS = {
     "billing.refund": "退款",
     "billing.adjust": "余额调整",
     
+    # PayPal 支付操作
+    "payment.paypal.order_created": "PayPal订单创建",
+    "payment.paypal.order_captured": "PayPal支付完成",
+    "payment.paypal.order_failed": "PayPal支付失败",
+    "payment.paypal.amount_mismatch": "PayPal金额不匹配",
+    "payment.paypal.webhook_received": "PayPal Webhook接收",
+    
     # 供应商管理
     "provider.create": "创建供应商",
     "provider.update": "更新供应商",
diff --git a/services/mcp-server/app/paypal_client.py b/services/mcp-server/app/paypal_client.py
new file mode 100644
index 0000000..4750bea
--- /dev/null
+++ b/services/mcp-server/app/paypal_client.py
@@ -0,0 +1,228 @@
+"""
+PayPal 客户端封装
+
+用于处理 PayPal 支付相关的 API 调用。
+支持创建订单、捕获支付、查询订单状态等操作。
+
+重要：这是客户支付的真金白银，所有操作必须有完整的日志记录。
+"""
+
+import logging
+from typing import Optional
+
+from paypalserversdk.http.auth.o_auth_2 import ClientCredentialsAuthCredentials
+from paypalserversdk.logging.configuration.api_logging_configuration import (
+    LoggingConfiguration,
+    RequestLoggingConfiguration,
+    ResponseLoggingConfiguration,
+)
+from paypalserversdk.paypal_serversdk_client import PaypalServersdkClient
+from paypalserversdk.controllers.orders_controller import OrdersController
+from paypalserversdk.models.order_request import OrderRequest
+from paypalserversdk.models.checkout_payment_intent import CheckoutPaymentIntent
+from paypalserversdk.models.purchase_unit_request import PurchaseUnitRequest
+from paypalserversdk.models.amount_with_breakdown import AmountWithBreakdown
+from paypalserversdk.api_helper import APIHelper
+from paypalserversdk.configuration import Environment
+
+from config import settings
+import structlog
+
+logger = structlog.get_logger(__name__)
+
+
+class PayPalClient:
+    """PayPal 客户端封装"""
+    
+    def __init__(self):
+        self._client: Optional[PaypalServersdkClient] = None
+        self._orders_controller: Optional[OrdersController] = None
+    
+    def _get_environment(self) -> Environment:
+        """获取 PayPal 环境配置"""
+        if settings.paypal_environment == "production":
+            return Environment.PRODUCTION
+        return Environment.SANDBOX
+    
+    def _get_client(self) -> PaypalServersdkClient:
+        """获取 PayPal SDK 客户端（懒加载）"""
+        if self._client is None:
+            self._client = PaypalServersdkClient(
+                client_credentials_auth_credentials=ClientCredentialsAuthCredentials(
+                    o_auth_client_id=settings.paypal_client_id,
+                    o_auth_client_secret=settings.paypal_client_secret,
+                ),
+                environment=self._get_environment(),
+                logging_configuration=LoggingConfiguration(
+                    log_level=logging.INFO,
+                    mask_sensitive_headers=True,
+                    request_logging_config=RequestLoggingConfiguration(
+                        log_body=True
+                    ),
+                    response_logging_config=ResponseLoggingConfiguration(
+                        log_body=True
+                    ),
+                ),
+            )
+        return self._client
+    
+    @property
+    def orders_controller(self) -> OrdersController:
+        """获取订单控制器"""
+        if self._orders_controller is None:
+            self._orders_controller = self._get_client().orders
+        return self._orders_controller
+    
+    async def create_order(self, amount: float, currency: str = "USD") -> dict:
+        """
+        创建 PayPal 订单
+        
+        Args:
+            amount: 支付金额
+            currency: 货币类型，默认 USD
+            
+        Returns:
+            包含 order_id 和状态的字典
+            
+        Raises:
+            Exception: PayPal API 调用失败
+        """
+        order_request = OrderRequest(
+            intent=CheckoutPaymentIntent.CAPTURE,
+            purchase_units=[
+                PurchaseUnitRequest(
+                    amount=AmountWithBreakdown(
+                        currency_code=currency,
+                        value=f"{amount:.2f}",
+                    ),
+                    description="Taiji AI Platform - EU Balance Recharge",
+                )
+            ],
+        )
+        
+        try:
+            response = self.orders_controller.create_order({"body": order_request})
+            
+            if response.body:
+                order = response.body
+                logger.info(
+                    "PayPal 订单创建成功",
+                    order_id=order.id,
+                    status=order.status,
+                    amount=amount
+                )
+                return {
+                    "order_id": order.id,
+                    "status": order.status,
+                    "links": [{"rel": link.rel, "href": link.href} for link in order.links] if order.links else []
+                }
+            else:
+                raise Exception("PayPal 返回空响应")
+                
+        except Exception as e:
+            logger.error("PayPal 订单创建失败", error=str(e))
+            raise
+    
+    async def capture_order(self, order_id: str) -> dict:
+        """
+        捕获 PayPal 订单（完成支付）
+        
+        Args:
+            order_id: PayPal 订单 ID
+            
+        Returns:
+            包含支付详情的字典
+            
+        Raises:
+            Exception: PayPal API 调用失败
+        """
+        try:
+            response = self.orders_controller.capture_order({"id": order_id})
+            
+            if response.body:
+                order = response.body
+                
+                # 提取支付信息
+                capture_info = {}
+                if order.purchase_units and len(order.purchase_units) > 0:
+                    pu = order.purchase_units[0]
+                    if pu.payments and pu.payments.captures and len(pu.payments.captures) > 0:
+                        capture = pu.payments.captures[0]
+                        capture_info = {
+                            "capture_id": capture.id,
+                            "amount": float(capture.amount.value) if capture.amount else 0,
+                            "currency": capture.amount.currency_code if capture.amount else "USD",
+                        }
+                
+                # 提取付款人信息
+                payer_info = {}
+                if order.payer:
+                    payer_info = {
+                        "payer_id": order.payer.payer_id,
+                        "email": order.payer.email_address,
+                        "name": f"{order.payer.name.given_name} {order.payer.name.surname}" if order.payer.name else None,
+                    }
+                
+                logger.info(
+                    "PayPal 订单捕获成功",
+                    order_id=order.id,
+                    status=order.status,
+                    capture_id=capture_info.get("capture_id")
+                )
+                
+                return {
+                    "order_id": order.id,
+                    "status": order.status,
+                    **capture_info,
+                    **payer_info,
+                    "raw_response": APIHelper.json_serialize(order),
+                }
+            else:
+                raise Exception("PayPal 返回空响应")
+                
+        except Exception as e:
+            logger.error("PayPal 订单捕获失败", order_id=order_id, error=str(e))
+            raise
+    
+    async def get_order(self, order_id: str) -> dict:
+        """
+        查询 PayPal 订单状态
+        
+        Args:
+            order_id: PayPal 订单 ID
+            
+        Returns:
+            订单详情
+            
+        Raises:
+            Exception: PayPal API 调用失败
+        """
+        try:
+            response = self.orders_controller.get_order({"id": order_id})
+            
+            if response.body:
+                order = response.body
+                return {
+                    "order_id": order.id,
+                    "status": order.status,
+                    "create_time": order.create_time,
+                    "update_time": order.update_time,
+                }
+            else:
+                raise Exception("PayPal 返回空响应")
+                
+        except Exception as e:
+            logger.error("PayPal 订单查询失败", order_id=order_id, error=str(e))
+            raise
+
+
+# 单例
+_paypal_client: Optional[PayPalClient] = None
+
+
+def get_paypal_client() -> PayPalClient:
+    """获取 PayPal 客户端单例"""
+    global _paypal_client
+    if _paypal_client is None:
+        _paypal_client = PayPalClient()
+    return _paypal_client
diff --git a/services/mcp-server/app/routes/__init__.py b/services/mcp-server/app/routes/__init__.py
index 6202205..c266660 100644
--- a/services/mcp-server/app/routes/__init__.py
+++ b/services/mcp-server/app/routes/__init__.py
@@ -12,6 +12,7 @@ from . import (
     platform_agent_quota,  # 平台 Agent 配额管理
     billing_webhook,  # LiteLLM Token计费webhook
     external_tools,  # 外部数据工具管理
+    paypal,  # PayPal 支付集成
 )
 
 
@@ -45,5 +46,8 @@ def register_routes(app: FastAPI) -> None:
         platform_agent_quota.channel_router,  # 渠道平台 Agent 配额管理
         platform_agent_quota.admin_router,  # 管理员平台 Agent 配额管理
         platform_agent_quota.user_router,  # 用户平台 Agent 配额管理
+        # PayPal 支付路由
+        paypal.router,  # PayPal 用户支付路由（需要认证）
+        paypal.webhook_router,  # PayPal Webhook 回调路由（无需认证，在 whitelist 路径下）
     ):
         app.include_router(router)
diff --git a/services/mcp-server/app/routes/auth.py b/services/mcp-server/app/routes/auth.py
index 7980642..1549cc8 100644
--- a/services/mcp-server/app/routes/auth.py
+++ b/services/mcp-server/app/routes/auth.py
@@ -545,9 +545,7 @@ async def register(req: UserCreate, db: AsyncSession = Depends(get_db)):
         status="active",
         is_active=True,
         is_admin=False,
-        balance=0,
         credit_limit=0,
-        eu_balance=0,
         total_eu_consumed=0,
     )
     
diff --git a/services/mcp-server/app/routes/paypal.py b/services/mcp-server/app/routes/paypal.py
new file mode 100644
index 0000000..7e9962f
--- /dev/null
+++ b/services/mcp-server/app/routes/paypal.py
@@ -0,0 +1,470 @@
+"""
+PayPal 支付路由
+用户在线充值功能
+
+重要：这是客户支付的真金白银，所有操作必须：
+1. 有完整的审计日志
+2. 有事务保护
+3. 有金额验证
+"""
+
+import structlog
+from datetime import datetime
+from decimal import Decimal
+from fastapi import APIRouter, Depends, HTTPException, status, Request
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+from pydantic import BaseModel, Field
+
+from database import get_db
+from models import User, Balance, RechargeRecord
+from app.auth import require_auth
+from app.schemas import SuccessResponse
+from app.paypal_client import get_paypal_client
+from app.billing import add_balance
+from app.audit import log_audit_event
+
+logger = structlog.get_logger(__name__)
+router = APIRouter(prefix="/api/user/billing/paypal", tags=["PayPal支付"])
+webhook_router = APIRouter(tags=["PayPal Webhook"])
+
+
+# ============= 请求/响应模型 =============
+
+class CreatePayPalOrderRequest(BaseModel):
+    """创建 PayPal 订单请求"""
+    amount: float = Field(..., gt=0, le=10000, description="充值金额 (USD)")
+    currency: str = Field("USD", pattern="^USD$", description="货币类型，目前仅支持 USD")
+
+
+class CapturePayPalOrderRequest(BaseModel):
+    """捕获 PayPal 订单请求"""
+    orderId: str = Field(..., min_length=1, description="PayPal 订单 ID")
+
+
+# ============= 用户路由 =============
+
+@router.post("/create-order", response_model=SuccessResponse)
+async def create_paypal_order(
+    req: CreatePayPalOrderRequest,
+    request: Request,
+    principal: dict = Depends(require_auth),
+    db: AsyncSession = Depends(get_db)
+):
+    """
+    创建 PayPal 订单
+    
+    用户发起充值请求，后端创建 PayPal 订单并返回订单 ID。
+    前端使用订单 ID 调用 PayPal JS SDK 弹出支付窗口。
+    
+    金额说明：
+    - 1 USD = 1 EU
+    - 最小充值金额：大于 0 USD
+    - 最大充值金额：10000 USD
+    """
+    user_id = principal.get("user_id")
+    order_id = None
+    
+    # 验证用户存在
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="用户不存在"
+        )
+    
+    try:
+        # 创建 PayPal 订单
+        paypal_client = get_paypal_client()
+        order_result = await paypal_client.create_order(
+            amount=req.amount,
+            currency=req.currency
+        )
+        order_id = order_result["order_id"]
+        
+        # 创建本地订单记录
+        recharge_record = RechargeRecord(
+            user_id=user_id,
+            amount=Decimal(str(req.amount)),
+            payment_method="paypal",
+            order_id=order_id,
+            status="pending",
+        )
+        db.add(recharge_record)
+        await db.commit()
+        
+        logger.info(
+            "PayPal 订单创建成功",
+            user_id=str(user_id),
+            order_id=order_id,
+            amount=req.amount
+        )
+        
+        # ========== 审计日志：订单创建成功 ==========
+        await log_audit_event(
+            action="payment.paypal.order_created",
+            resource_type="paypal_order",
+            resource_id=order_id,
+            user_id=str(user_id),
+            success=True,
+            details={
+                "amount": req.amount,
+                "currency": req.currency,
+                "eu_amount": req.amount,
+                "paypal_status": order_result["status"],
+            },
+            request=request,
+            db=db
+        )
+        
+        return SuccessResponse(
+            data={
+                "orderId": order_id,
+                "status": order_result["status"],
+                "amount": req.amount,
+                "currency": req.currency,
+                "euAmount": req.amount,
+            },
+            message="订单创建成功，请完成支付"
+        )
+        
+    except Exception as e:
+        logger.error("创建 PayPal 订单失败", user_id=str(user_id), error=str(e))
+        
+        # ========== 审计日志：订单创建失败 ==========
+        await log_audit_event(
+            action="payment.paypal.order_created",
+            resource_type="paypal_order",
+            resource_id=order_id,
+            user_id=str(user_id),
+            success=False,
+            details={"amount": req.amount, "currency": req.currency},
+            error_message=str(e),
+            request=request,
+            db=db
+        )
+        
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"创建订单失败: {str(e)}"
+        )
+
+
+@router.post("/capture-order", response_model=SuccessResponse)
+async def capture_paypal_order(
+    req: CapturePayPalOrderRequest,
+    request: Request,
+    principal: dict = Depends(require_auth),
+    db: AsyncSession = Depends(get_db)
+):
+    """
+    捕获 PayPal 订单（完成支付）
+    
+    用户在 PayPal 完成支付后，前端调用此接口验证支付并完成充值。
+    
+    流程：
+    1. 验证订单属于当前用户
+    2. 调用 PayPal API 捕获支付
+    3. 验证支付金额
+    4. 增加用户 EU 余额
+    5. 更新订单状态
+    """
+    user_id = principal.get("user_id")
+    
+    # 查找本地订单记录
+    result = await db.execute(
+        select(RechargeRecord).where(
+            RechargeRecord.order_id == req.orderId,
+            RechargeRecord.user_id == user_id,
+            RechargeRecord.payment_method == "paypal"
+        )
+    )
+    recharge_record = result.scalar_one_or_none()
+    
+    if not recharge_record:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="订单不存在或不属于当前用户"
+        )
+    
+    if recharge_record.status == "success":
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="订单已完成，请勿重复操作"
+        )
+    
+    try:
+        # 捕获 PayPal 订单
+        paypal_client = get_paypal_client()
+        capture_result = await paypal_client.capture_order(req.orderId)
+        
+        if capture_result["status"] != "COMPLETED":
+            recharge_record.status = "failed"
+            await db.commit()
+            raise HTTPException(
+                status_code=status.HTTP_400_BAD_REQUEST,
+                detail=f"支付未完成，状态: {capture_result['status']}"
+            )
+        
+        # 验证支付金额（严格模式：金额必须完全匹配）
+        captured_amount = Decimal(str(capture_result.get("amount", 0)))
+        expected_amount = recharge_record.amount
+        
+        if captured_amount != expected_amount:
+            logger.error(
+                "支付金额不匹配，拒绝充值",
+                order_id=req.orderId,
+                expected=float(expected_amount),
+                captured=float(captured_amount),
+                user_id=str(user_id)
+            )
+            recharge_record.status = "amount_mismatch"
+            await db.commit()
+            
+            # ========== 审计日志：金额不匹配 ==========
+            await log_audit_event(
+                action="payment.paypal.amount_mismatch",
+                resource_type="paypal_order",
+                resource_id=req.orderId,
+                user_id=str(user_id),
+                success=False,
+                details={
+                    "expected_amount": float(expected_amount),
+                    "captured_amount": float(captured_amount),
+                },
+                error_message=f"支付金额不匹配: 期望 ${expected_amount}, 实际 ${captured_amount}",
+                request=request,
+                db=db
+            )
+            
+            raise HTTPException(
+                status_code=status.HTTP_400_BAD_REQUEST,
+                detail=f"支付金额不匹配: 期望 ${expected_amount}, 实际 ${captured_amount}"
+            )
+        
+        # 增加用户余额
+        eu_amount = captured_amount  # 1 USD = 1 EU
+        success, message = await add_balance(
+            user_id=str(user_id),
+            amount=eu_amount,
+            db=db,
+            description=f"PayPal 充值 (订单: {req.orderId})",
+            auto_commit=False  # 不自动提交，等待订单状态更新后一起提交
+        )
+        
+        if not success:
+            await db.rollback()
+            raise HTTPException(
+                status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+                detail=f"余额更新失败: {message}"
+            )
+        
+        # 更新订单状态
+        recharge_record.status = "success"
+        recharge_record.completed_at = datetime.utcnow()
+        
+        # 统一提交事务
+        await db.commit()
+        
+        # 获取新余额
+        balance_result = await db.execute(
+            select(Balance).where(Balance.user_id == user_id)
+        )
+        balance = balance_result.scalar_one_or_none()
+        new_balance = float(balance.eu_balance) if balance else 0
+        
+        logger.info(
+            "PayPal 充值成功",
+            user_id=str(user_id),
+            order_id=req.orderId,
+            amount=float(captured_amount),
+            new_balance=new_balance
+        )
+        
+        # ========== 审计日志：支付成功 ==========
+        await log_audit_event(
+            action="payment.paypal.order_captured",
+            resource_type="paypal_order",
+            resource_id=req.orderId,
+            user_id=str(user_id),
+            success=True,
+            details={
+                "amount": float(captured_amount),
+                "eu_amount": float(eu_amount),
+                "new_balance": new_balance,
+                "capture_id": capture_result.get("capture_id"),
+                "payer_email": capture_result.get("email"),
+                "payer_id": capture_result.get("payer_id"),
+            },
+            request=request,
+            db=db
+        )
+        
+        return SuccessResponse(
+            data={
+                "orderId": req.orderId,
+                "status": "COMPLETED",
+                "amount": float(captured_amount),
+                "euAmount": float(eu_amount),
+                "newBalance": new_balance,
+                "captureId": capture_result.get("capture_id"),
+                "payerEmail": capture_result.get("email"),
+            },
+            message=f"充值成功，已增加 {eu_amount} EU"
+        )
+        
+    except HTTPException:
+        # HTTPException 已经处理过，直接抛出
+        raise
+        
+    except Exception as e:
+        await db.rollback()
+        logger.error(
+            "捕获 PayPal 订单失败",
+            order_id=req.orderId,
+            user_id=str(user_id),
+            error=str(e),
+            error_type=type(e).__name__
+        )
+        
+        # ========== 审计日志：系统异常 ==========
+        await log_audit_event(
+            action="payment.paypal.order_failed",
+            resource_type="paypal_order",
+            resource_id=req.orderId,
+            user_id=str(user_id),
+            success=False,
+            details={"error_type": type(e).__name__},
+            error_message=str(e),
+            request=request,
+            db=db
+        )
+        
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"支付验证失败: {str(e)}"
+        )
+
+
+@router.get("/order/{order_id}", response_model=SuccessResponse)
+async def get_paypal_order(
+    order_id: str,
+    principal: dict = Depends(require_auth),
+    db: AsyncSession = Depends(get_db)
+):
+    """
+    查询 PayPal 订单状态
+    """
+    user_id = principal.get("user_id")
+    
+    # 查找本地订单记录
+    result = await db.execute(
+        select(RechargeRecord).where(
+            RechargeRecord.order_id == order_id,
+            RechargeRecord.user_id == user_id,
+            RechargeRecord.payment_method == "paypal"
+        )
+    )
+    recharge_record = result.scalar_one_or_none()
+    
+    if not recharge_record:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="订单不存在"
+        )
+    
+    return SuccessResponse(
+        data={
+            "orderId": order_id,
+            "status": recharge_record.status,
+            "amount": float(recharge_record.amount),
+            "euAmount": float(recharge_record.amount),
+            "createdAt": recharge_record.created_at.isoformat() if recharge_record.created_at else None,
+            "completedAt": recharge_record.completed_at.isoformat() if recharge_record.completed_at else None,
+        }
+    )
+
+
+# ============= Webhook 路由 =============
+
+@webhook_router.post("/whitelist/payment/callback/paypal")
+async def paypal_webhook(
+    request: Request,
+    db: AsyncSession = Depends(get_db)
+):
+    """
+    PayPal Webhook 回调
+    
+    用于接收 PayPal 异步通知，处理边缘情况（如用户关闭页面但支付已完成）。
+    
+    支持的事件类型：
+    - PAYMENT.CAPTURE.COMPLETED: 支付捕获完成
+    - PAYMENT.CAPTURE.DENIED: 支付被拒绝
+    - PAYMENT.CAPTURE.REFUNDED: 支付已退款
+    """
+    try:
+        # 获取请求体
+        body = await request.json()
+        
+        # 获取 PayPal 签名头（用于验证）
+        headers = {
+            "PayPal-Transmission-Id": request.headers.get("PayPal-Transmission-Id"),
+            "PayPal-Transmission-Time": request.headers.get("PayPal-Transmission-Time"),
+            "PayPal-Transmission-Sig": request.headers.get("PayPal-Transmission-Sig"),
+            "PayPal-Cert-Url": request.headers.get("PayPal-Cert-Url"),
+            "PayPal-Auth-Algo": request.headers.get("PayPal-Auth-Algo"),
+        }
+        
+        # TODO: 验证 Webhook 签名
+        # 生产环境必须验证签名，防止伪造请求
+        # 使用 PayPal Webhook Signature Verification API
+        
+        event_type = body.get("event_type")
+        resource = body.get("resource", {})
+        
+        logger.info(
+            "收到 PayPal Webhook",
+            event_type=event_type,
+            resource_id=resource.get("id")
+        )
+        
+        # ========== 审计日志：Webhook 接收 ==========
+        await log_audit_event(
+            action="payment.paypal.webhook_received",
+            resource_type="paypal_webhook",
+            resource_id=body.get("id"),
+            user_id=None,
+            success=True,
+            details={
+                "event_type": event_type,
+                "resource_id": resource.get("id"),
+            },
+            request=request,
+            db=db
+        )
+        
+        if event_type == "PAYMENT.CAPTURE.COMPLETED":
+            # 支付完成
+            capture_id = resource.get("id")
+            # 根据 capture_id 查找并更新订单
+            # 这里作为备份机制，主要逻辑在 capture-order 接口
+            logger.info("PayPal 支付完成 Webhook", capture_id=capture_id)
+            
+        elif event_type == "PAYMENT.CAPTURE.DENIED":
+            # 支付被拒绝
+            capture_id = resource.get("id")
+            logger.warning("PayPal 支付被拒绝", capture_id=capture_id)
+            
+        elif event_type == "PAYMENT.CAPTURE.REFUNDED":
+            # 支付已退款
+            capture_id = resource.get("id")
+            logger.info("PayPal 支付已退款", capture_id=capture_id)
+            # TODO: 处理退款逻辑，扣减用户余额
+        
+        return {"success": True}
+        
+    except Exception as e:
+        logger.error("处理 PayPal Webhook 失败", error=str(e))
+        # 返回 200 避免 PayPal 重试
+        return {"success": False, "error": str(e)}
diff --git a/services/mcp-server/config.py b/services/mcp-server/config.py
index 5ee28ec..029aec9 100644
--- a/services/mcp-server/config.py
+++ b/services/mcp-server/config.py
@@ -106,6 +106,19 @@ class Settings(BaseSettings):
     alipay_app_id: str = os.getenv("ALIPAY_APP_ID", "")
     wechat_pay_app_id: str = os.getenv("WECHAT_PAY_APP_ID", "")
     
+    # PayPal 支付配置
+    paypal_client_id: str = os.getenv("PAYPAL_CLIENT_ID", "")
+    paypal_client_secret: str = os.getenv("PAYPAL_CLIENT_SECRET", "")
+    paypal_environment: str = os.getenv("PAYPAL_ENVIRONMENT", "sandbox")  # sandbox 或 production
+    paypal_webhook_id: str = os.getenv("PAYPAL_WEBHOOK_ID", "")  # 用于验证 Webhook 签名
+    
+    @property
+    def paypal_api_base(self) -> str:
+        """获取 PayPal API 基础 URL"""
+        if self.paypal_environment == "production":
+            return "https://api-m.paypal.com"
+        return "https://api-m.sandbox.paypal.com"
+    
     # 云存储设置（Azure Blob Storage）
     azure_storage_connection_string: str = os.getenv("AZURE_STORAGE_CONNECTION_STRING", "")
     s3_bucket: str = os.getenv("S3_BUCKET", "taiji-ai-exports")
diff --git a/services/mcp-server/requirements.txt b/services/mcp-server/requirements.txt
index 568744e..b859dc4 100644
--- a/services/mcp-server/requirements.txt
+++ b/services/mcp-server/requirements.txt
@@ -43,4 +43,7 @@ psutil==5.9.8
 # 其他
 Jinja2==3.1.3
 MarkupSafe==2.1.3
-pydantic[email]
\ No newline at end of file
+pydantic[email]
+
+# PayPal 支付
+paypal-server-sdk>=0.5.0
\ No newline at end of file