diff --git a/agent/checkpoint_manager.py b/agent/checkpoint_manager.py
index 3c5a796..d8afc34 100644
--- a/agent/checkpoint_manager.py
+++ b/agent/checkpoint_manager.py
@@ -5,7 +5,8 @@
 import asyncio
 import logging
 import os
-from typing import Optional
+from datetime import datetime, timedelta, timezone
+from typing import Optional, List, Dict, Any
 
 import aiosqlite
 from langgraph.checkpoint.sqlite.aio import AsyncSqliteSaver
@@ -15,6 +16,9 @@ from utils.settings import (
     CHECKPOINT_WAL_MODE,
     CHECKPOINT_BUSY_TIMEOUT,
     CHECKPOINT_POOL_SIZE,
+    CHECKPOINT_CLEANUP_ENABLED,
+    CHECKPOINT_CLEANUP_INTERVAL_HOURS,
+    CHECKPOINT_CLEANUP_OLDER_THAN_DAYS,
 )
 
 logger = logging.getLogger('app')
@@ -38,6 +42,9 @@ class CheckpointerManager:
         self._closed = False
         self._pool_size = CHECKPOINT_POOL_SIZE
         self._db_path = CHECKPOINT_DB_PATH
+        # 清理调度任务
+        self._cleanup_task: Optional[asyncio.Task] = None
+        self._cleanup_stop_event = asyncio.Event()
 
     async def initialize(self) -> None:
         """初始化连接池"""
@@ -131,6 +138,16 @@ class CheckpointerManager:
         if self._closed:
             return
 
+        # 停止清理任务
+        if self._cleanup_task is not None:
+            self._cleanup_stop_event.set()
+            try:
+                self._cleanup_task.cancel()
+                await asyncio.sleep(0.1)  # 给任务一点时间清理
+            except asyncio.CancelledError:
+                pass
+            self._cleanup_task = None
+
         async with self._lock:
             if self._closed:
                 return
@@ -160,6 +177,181 @@ class CheckpointerManager:
             "closed": self._closed
         }
 
+    # ============================================================
+    # Checkpoint 清理方法
+    # ============================================================
+
+    async def get_all_thread_ids(self) -> List[str]:
+        """
+        获取数据库中所有唯一的 thread_id
+
+        Returns:
+            List[str]: 所有 thread_id 列表
+        """
+        if not self._initialized:
+            return []
+
+        conn = aiosqlite.connect(self._db_path)
+        await conn.__aenter__()
+
+        try:
+            cursor = await conn.execute(
+                "SELECT DISTINCT thread_id FROM checkpoints"
+            )
+            rows = await cursor.fetchall()
+            return [row[0] for row in rows]
+        finally:
+            await conn.close()
+
+    async def get_thread_last_activity(self, thread_id: str) -> Optional[datetime]:
+        """
+        获取指定 thread 的最后活动时间
+
+        通过查询该 thread 最新的 checkpoint 中的 ts 字段获取时间
+
+        Args:
+            thread_id: 线程ID
+
+        Returns:
+            datetime: 最后活动时间，如果找不到则返回 None
+        """
+        if not self._initialized:
+            return None
+
+        checkpointer = await self.acquire_for_agent()
+
+        try:
+            config = {"configurable": {"thread_id": thread_id}}
+            result = checkpointer.alist(config=config, limit=1)
+
+            last_checkpoint = None
+            async for item in result:
+                last_checkpoint = item
+                break
+
+            if last_checkpoint and last_checkpoint.checkpoint:
+                ts_str = last_checkpoint.checkpoint.get("ts")
+                if ts_str:
+                    # 解析 ISO 格式时间戳
+                    return datetime.fromisoformat(ts_str.replace("Z", "+00:00"))
+        except Exception as e:
+            logger.warning(f"Error getting last activity for thread {thread_id}: {e}")
+        finally:
+            await self.return_to_pool(checkpointer)
+
+        return None
+
+    async def cleanup_old_threads(self, older_than_days: int = None) -> Dict[str, Any]:
+        """
+        清理超过指定天数未活动的 thread
+
+        Args:
+            older_than_days: 清理多少天前的数据，默认使用配置值
+
+        Returns:
+            Dict: 清理统计信息
+                - threads_deleted: 删除的 thread 数量
+                - threads_scanned: 扫描的 thread 总数
+                - cutoff_time: 截止时间
+        """
+        if older_than_days is None:
+            older_than_days = CHECKPOINT_CLEANUP_OLDER_THAN_DAYS
+
+        # 使用带时区的时间，避免比较时出错
+        cutoff_time = datetime.now(timezone.utc) - timedelta(days=older_than_days)
+        logger.info(f"Starting checkpoint cleanup: removing threads inactive since {cutoff_time.isoformat()}")
+
+        all_thread_ids = await self.get_all_thread_ids()
+        threads_deleted = 0
+        threads_scanned = len(all_thread_ids)
+
+        checkpointer = await self.acquire_for_agent()
+
+        try:
+            for thread_id in all_thread_ids:
+                try:
+                    last_activity = await self.get_thread_last_activity(thread_id)
+
+                    if last_activity and last_activity < cutoff_time:
+                        # 删除旧 thread
+                        config = {"configurable": {"thread_id": thread_id}}
+                        await checkpointer.adelete_thread(config)
+                        threads_deleted += 1
+                        logger.debug(f"Deleted old thread: {thread_id} (last activity: {last_activity.isoformat()})")
+                except Exception as e:
+                    logger.warning(f"Error processing thread {thread_id}: {e}")
+
+        finally:
+            await self.return_to_pool(checkpointer)
+
+        result = {
+            "threads_deleted": threads_deleted,
+            "threads_scanned": threads_scanned,
+            "cutoff_time": cutoff_time.isoformat(),
+            "older_than_days": older_than_days
+        }
+
+        logger.info(f"Checkpoint cleanup completed: {result}")
+        return result
+
+    async def _cleanup_loop(self):
+        """后台清理循环"""
+        interval_seconds = CHECKPOINT_CLEANUP_INTERVAL_HOURS * 3600
+
+        logger.info(
+            f"Checkpoint cleanup scheduler started: "
+            f"interval={CHECKPOINT_CLEANUP_INTERVAL_HOURS}h, "
+            f"older_than={CHECKPOINT_CLEANUP_OLDER_THAN_DAYS} days"
+        )
+
+        while not self._cleanup_stop_event.is_set():
+            try:
+                # 等待间隔时间或停止信号
+                try:
+                    await asyncio.wait_for(
+                        self._cleanup_stop_event.wait(),
+                        timeout=interval_seconds
+                    )
+                    # 收到停止信号，退出循环
+                    break
+                except asyncio.TimeoutError:
+                    # 超时，执行清理任务
+                    pass
+
+                if self._cleanup_stop_event.is_set():
+                    break
+
+                # 执行清理
+                await self.cleanup_old_threads()
+
+            except asyncio.CancelledError:
+                logger.info("Cleanup task cancelled")
+                break
+            except Exception as e:
+                logger.error(f"Error in cleanup loop: {e}")
+
+        logger.info("Checkpoint cleanup scheduler stopped")
+
+    def start_cleanup_scheduler(self):
+        """启动后台定时清理任务"""
+        if not CHECKPOINT_CLEANUP_ENABLED:
+            logger.info("Checkpoint cleanup is disabled")
+            return
+
+        if self._cleanup_task is not None and not self._cleanup_task.done():
+            logger.warning("Cleanup scheduler is already running")
+            return
+
+        # 创建新的事件循环（如果需要在后台运行）
+        try:
+            loop = asyncio.get_running_loop()
+        except RuntimeError:
+            loop = asyncio.new_event_loop()
+            asyncio.set_event_loop(loop)
+
+        self._cleanup_task = loop.create_task(self._cleanup_loop())
+        logger.info("Cleanup scheduler task created")
+
 
 # 全局单例
 _global_manager: Optional[CheckpointerManager] = None
diff --git a/fastapi_app.py b/fastapi_app.py
index f5302fa..79def96 100644
--- a/fastapi_app.py
+++ b/fastapi_app.py
@@ -26,15 +26,33 @@ async def lifespan(app: FastAPI):
     """FastAPI 应用生命周期管理"""
     # 启动时初始化
     logger.info("Starting up...")
-    from agent.checkpoint_manager import init_global_checkpointer
+    from agent.checkpoint_manager import (
+        init_global_checkpointer,
+        get_checkpointer_manager,
+        close_global_checkpointer
+    )
+    from utils.settings import CHECKPOINT_CLEANUP_ENABLED
+
     await init_global_checkpointer()
     logger.info("Global checkpointer initialized")
 
+    # 启动 checkpoint 清理调度器
+    if CHECKPOINT_CLEANUP_ENABLED:
+        manager = get_checkpointer_manager()
+        # 启动时立即执行一次清理
+        try:
+            result = await manager.cleanup_old_threads()
+            logger.info(f"Startup cleanup completed: {result}")
+        except Exception as e:
+            logger.warning(f"Startup cleanup failed (non-fatal): {e}")
+        # 启动定时清理调度器
+        manager.start_cleanup_scheduler()
+        logger.info("Checkpoint cleanup scheduler started")
+
     yield
 
     # 关闭时清理
     logger.info("Shutting down...")
-    from agent.checkpoint_manager import close_global_checkpointer
     await close_global_checkpointer()
     logger.info("Global checkpointer closed")
 
diff --git a/utils/settings.py b/utils/settings.py
index e2340ae..abd4076 100644
--- a/utils/settings.py
+++ b/utils/settings.py
@@ -59,4 +59,16 @@ CHECKPOINT_BUSY_TIMEOUT = int(os.getenv("CHECKPOINT_BUSY_TIMEOUT", "10000"))
 # 同时可以持有的最大连接数
 CHECKPOINT_POOL_SIZE = int(os.getenv("CHECKPOINT_POOL_SIZE", "15"))
 
+# Checkpoint 自动清理配置
+# 是否启用自动清理旧 session
+CHECKPOINT_CLEANUP_ENABLED = os.getenv("CHECKPOINT_CLEANUP_ENABLED", "true") == "true"
+
+# 清理间隔（小时）
+# 每隔多少小时执行一次清理任务
+CHECKPOINT_CLEANUP_INTERVAL_HOURS = int(os.getenv("CHECKPOINT_CLEANUP_INTERVAL_HOURS", "24"))
+
+# 清理多少天前的数据
+# 超过 N 天未活动的 thread 会被删除
+CHECKPOINT_CLEANUP_OLDER_THAN_DAYS = int(os.getenv("CHECKPOINT_CLEANUP_OLDER_THAN_DAYS", "3"))
+