diff --git a/src/chat/memory_system/vector_instant_memory.py b/src/chat/memory_system/vector_instant_memory.py
index 360d52bec..9c7824d9a 100644
--- a/src/chat/memory_system/vector_instant_memory.py
+++ b/src/chat/memory_system/vector_instant_memory.py
@@ -87,22 +87,38 @@ class VectorInstantMemoryV2:
         """清理过期的聊天记录"""
         try:
             expire_time = time.time() - (self.retention_hours * 3600)
-            
-            # 使用 where 条件来删除过期记录
-            # 注意: ChromaDB 的 where 过滤器目前对 timestamp 的 $lt 操作支持可能有限
-            # 一个更可靠的方法是 get() -> filter -> delete()
-            # 但为了简化，我们先尝试直接 delete
-            
-            # TODO: 确认 ChromaDB 对 $lt 在 metadata 上的支持。如果不支持，需要实现 get-filter-delete 模式。
-            vector_db_service.delete(
+
+            # 采用 get -> filter -> delete 模式，避免复杂的 where 查询
+            # 1. 获取当前 chat_id 的所有文档
+            results = vector_db_service.get(
                 collection_name=self.collection_name,
-                where={
-                    "chat_id": self.chat_id,
-                    "timestamp": {"$lt": expire_time}
-                }
+                where={"chat_id": self.chat_id},
+                include=["metadatas"]
             )
-            logger.info(f"已为 chat_id '{self.chat_id}' 触发过期记录清理")
-                
+
+            if not results or not results.get('ids'):
+                logger.info(f"chat_id '{self.chat_id}' 没有找到任何记录，无需清理")
+                return
+
+            # 2. 在内存中过滤出过期的文档
+            expired_ids = []
+            metadatas = results.get('metadatas', [])
+            ids = results.get('ids', [])
+
+            for i, metadata in enumerate(metadatas):
+                if metadata and metadata.get('timestamp', float('inf')) < expire_time:
+                    expired_ids.append(ids[i])
+
+            # 3. 如果有过期文档，根据 ID 进行删除
+            if expired_ids:
+                vector_db_service.delete(
+                    collection_name=self.collection_name,
+                    ids=expired_ids
+                )
+                logger.info(f"为 chat_id '{self.chat_id}' 清理了 {len(expired_ids)} 条过期记录")
+            else:
+                logger.info(f"chat_id '{self.chat_id}' 没有需要清理的过期记录")
+
         except Exception as e:
             logger.error(f"清理过期记录失败: {e}")
     
diff --git a/src/common/vector_db/base.py b/src/common/vector_db/base.py
index 56494ab73..e94b74cba 100644
--- a/src/common/vector_db/base.py
+++ b/src/common/vector_db/base.py
@@ -93,6 +93,34 @@ class VectorDBBase(ABC):
         """
         pass
 
+    @abstractmethod
+    def get(
+        self,
+        collection_name: str,
+        ids: Optional[List[str]] = None,
+        where: Optional[Dict[str, Any]] = None,
+        limit: Optional[int] = None,
+        offset: Optional[int] = None,
+        where_document: Optional[Dict[str, Any]] = None,
+        include: Optional[List[str]] = None,
+    ) -> Dict[str, Any]:
+        """
+        根据条件从集合中获取数据。
+
+        Args:
+            collection_name (str): 目标集合的名称。
+            ids (Optional[List[str]], optional): 要获取的条目的 ID 列表。Defaults to None.
+            where (Optional[Dict[str, Any]], optional): 基于元数据的过滤条件。Defaults to None.
+            limit (Optional[int], optional): 返回结果的数量限制。Defaults to None.
+            offset (Optional[int], optional): 返回结果的偏移量。Defaults to None.
+            where_document (Optional[Dict[str, Any]], optional): 基于文档内容的过滤条件。Defaults to None.
+            include (Optional[List[str]], optional): 指定返回的数据字段 (e.g., ["metadatas", "documents"])。Defaults to None.
+
+        Returns:
+            Dict[str, Any]: 获取到的数据。
+        """
+        pass
+
     @abstractmethod
     def count(self, collection_name: str) -> int:
         """
diff --git a/src/common/vector_db/chromadb_impl.py b/src/common/vector_db/chromadb_impl.py
index a43c2a6d8..8e9313b3b 100644
--- a/src/common/vector_db/chromadb_impl.py
+++ b/src/common/vector_db/chromadb_impl.py
@@ -102,6 +102,32 @@ class ChromaDBImpl(VectorDBBase):
                 logger.error(f"查询集合 '{collection_name}' 失败: {e}")
         return {}
 
+    def get(
+        self,
+        collection_name: str,
+        ids: Optional[List[str]] = None,
+        where: Optional[Dict[str, Any]] = None,
+        limit: Optional[int] = None,
+        offset: Optional[int] = None,
+        where_document: Optional[Dict[str, Any]] = None,
+        include: Optional[List[str]] = None,
+    ) -> Dict[str, Any]:
+        """根据条件从集合中获取数据"""
+        collection = self.get_or_create_collection(collection_name)
+        if collection:
+            try:
+                return collection.get(
+                    ids=ids,
+                    where=where,
+                    limit=limit,
+                    offset=offset,
+                    where_document=where_document,
+                    include=include,
+                )
+            except Exception as e:
+                logger.error(f"从集合 '{collection_name}' 获取数据失败: {e}")
+        return {}
+
     def delete(
         self,
         collection_name: str,