diff --git a/backend/app/backend.py b/backend/app/backend.py
index c8ea409..05825d4 100644
--- a/backend/app/backend.py
+++ b/backend/app/backend.py
@@ -4,7 +4,8 @@ FastAPI 后端 - 支持动态模型切换，使用 PostgreSQL 持久化记忆
 """
 
 import os
-from app.config import DB_URI, BACKEND_PORT
+# from app.config import DB_URI, BACKEND_PORT
+from app.config import BACKEND_PORT
 import uuid
 import json
 from contextlib import asynccontextmanager
@@ -14,7 +15,7 @@ from fastapi import FastAPI, HTTPException, WebSocket, WebSocketDisconnect, Depe
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import StreamingResponse
 from pydantic import BaseModel
-from langgraph.checkpoint.postgres.aio import AsyncPostgresSaver
+from langgraph.checkpoint.memory import MemorySaver
 from .agent.service import AIAgentService
 from .agent.history import ThreadHistoryService
 from app.core.human_review import (
@@ -26,56 +27,42 @@ from app.core.human_review import (
 from app.subgraphs.contact.api_client import ContactAPIClient
 from app.subgraphs.dictionary.api_client import DictionaryAPIClient
 from app.subgraphs.news_analysis.api_client import NewsAPIClient
-from .db.init_db import init_subgraph_tables
-from .db.models import ContactRepository, DictionaryRepository, NewsRepository
+# from .db.init_db import init_subgraph_tables
+# from .db.models import ContactRepository, DictionaryRepository, NewsRepository
 from app.logger import info, error
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
-    """应用生命周期管理：创建并注入全局服务"""
-    # 1. 创建数据库连接池并初始化表（仅 checkpointer）
-    async with AsyncPostgresSaver.from_conn_string(DB_URI) as checkpointer:
-        await checkpointer.setup()
-        
-        # 1.5 初始化子图表
-        await init_subgraph_tables(checkpointer.conn)
-        
-        # 2. 构建 AI Agent 服务
-        agent_service = AIAgentService(checkpointer)
-        await agent_service.initialize()
-        
-        # 3. 创建历史查询服务（保持原有的 checkpointer 参数）
-        history_service = ThreadHistoryService(checkpointer)
-        
-        # 3.5 创建子图 Repositories
-        contact_repo = ContactRepository(checkpointer.conn)
-        dictionary_repo = DictionaryRepository(checkpointer.conn)
-        news_repo = NewsRepository(checkpointer.conn)
-        
-        # 3.6 创建子图 API 客户端（真实数据库模式）
-        contact_api = ContactAPIClient(checkpointer.conn)
-        dictionary_api = DictionaryAPIClient(word_repository=dictionary_repo)
-        news_api = NewsAPIClient(news_repository=news_repo)
-        
-        # 4. 创建审核管理器
-        review_manager = ReviewManager(InMemoryReviewStore())
-        
-        # 5. 将服务实例存入 app.state
-        app.state.agent_service = agent_service
-        app.state.history_service = history_service
-        app.state.review_manager = review_manager
-        app.state.contact_api = contact_api
-        app.state.dictionary_api = dictionary_api
-        app.state.news_api = news_api
-        app.state.contact_repo = contact_repo
-        app.state.dictionary_repo = dictionary_repo
-        app.state.news_repo = news_repo
-        
-        # 应用运行中...
-        yield
-        
-        # 6. 关闭时自动清理数据库连接（async with 负责）
-        info("🛑 应用关闭，数据库连接池已释放")
+    """应用生命周期管理：创建并注入全局服务（临时用内存 checkpoint）"""
+    # 1. 创建内存 checkpointer（临时测试）
+    checkpointer = MemorySaver()
+    
+    # 2. 构建 AI Agent 服务
+    agent_service = AIAgentService(checkpointer)
+    await agent_service.initialize()
+    
+    # 3. 创建历史查询服务（保持原有的 checkpointer 参数）
+    history_service = ThreadHistoryService(checkpointer)
+    
+    # 4. 创建审核管理器
+    review_manager = ReviewManager(InMemoryReviewStore())
+    
+    # 5. 将服务实例存入 app.state
+    app.state.agent_service = agent_service
+    app.state.history_service = history_service
+    app.state.review_manager = review_manager
+    app.state.contact_api = ContactAPIClient()
+    app.state.dictionary_api = DictionaryAPIClient()
+    app.state.news_api = NewsAPIClient()
+    app.state.contact_repo = None
+    app.state.dictionary_repo = None
+    app.state.news_repo = None
+    
+    # 应用运行中...
+    yield
+    
+    # 6. 关闭时清理
+    info("🛑 应用关闭")
 
 app = FastAPI(lifespan=lifespan)
 
diff --git a/docker/docker-compose.yml b/docker/docker-compose.yml
index 8c343a0..b40ccc0 100644
--- a/docker/docker-compose.yml
+++ b/docker/docker-compose.yml
@@ -15,7 +15,7 @@ services:
       # =========================================================================
       # PostgreSQL 数据库配置
       # =========================================================================
-      - DB_HOST=115.190.121.151
+      - DB_HOST=ai-postgres
       - DB_PORT=5432
       - DB_USER=postgres
       - DB_PASSWORD=${DB_PASSWORD:?请配置 DB_PASSWORD（本地：.env 文件 | CI/CD：Secrets）}  # ⭐ 敏感密钥配置