diff --git a/server/knowledge_base/kb_service/base.py b/server/knowledge_base/kb_service/base.py
index d506f63..09766e6 100644
--- a/server/knowledge_base/kb_service/base.py
+++ b/server/knowledge_base/kb_service/base.py
@@ -77,6 +77,7 @@ class KBService(ABC):
         """
         docs = kb_file.file2text()
         if docs:
+            self.delete_doc(kb_file)
             embeddings = self._load_embeddings()
             self.do_add_doc(docs, embeddings)
             status = add_doc_to_db(kb_file)
diff --git a/server/knowledge_base/kb_service/faiss_kb_service.py b/server/knowledge_base/kb_service/faiss_kb_service.py
index 5c8376f..5953c3a 100644
--- a/server/knowledge_base/kb_service/faiss_kb_service.py
+++ b/server/knowledge_base/kb_service/faiss_kb_service.py
@@ -41,7 +41,23 @@ def load_vector_store(
     vs_path = get_vs_path(knowledge_base_name)
     if embeddings is None:
         embeddings = load_embeddings(embed_model, embed_device)
-    search_index = FAISS.load_local(vs_path, embeddings, normalize_L2=True)
+
+    if not os.path.exists(vs_path):
+        os.makedirs(vs_path)
+
+    if "index.faiss" in os.listdir(vs_path):
+        search_index = FAISS.load_local(vs_path, embeddings, normalize_L2=True)
+    else:
+        # create an empty vector store
+        doc = Document(page_content="init", metadata={})
+        search_index = FAISS.from_documents([doc], embeddings, normalize_L2=True)
+        ids = [k for k, v in search_index.docstore._dict.items()]
+        search_index.delete(ids)
+        search_index.save_local(vs_path)
+    
+    if tick == 0: # vector store is loaded first time
+        _VECTOR_STORE_TICKS[knowledge_base_name] = 0
+
     return search_index
 
 
@@ -74,8 +90,10 @@ class FaissKBService(KBService):
     def do_create_kb(self):
         if not os.path.exists(self.vs_path):
             os.makedirs(self.vs_path)
+        load_vector_store(self.kb_name)
 
     def do_drop_kb(self):
+        self.clear_vs()
         shutil.rmtree(self.kb_path)
 
     def do_search(self,
@@ -94,37 +112,35 @@ class FaissKBService(KBService):
                    docs: List[Document],
                    embeddings: Embeddings,
                    ):
-        if os.path.exists(self.vs_path) and "index.faiss" in os.listdir(self.vs_path):
-            vector_store = FAISS.load_local(self.vs_path, embeddings, normalize_L2=True)
-            vector_store.add_documents(docs)
-            torch_gc()
-        else:
-            if not os.path.exists(self.vs_path):
-                os.makedirs(self.vs_path)
-            vector_store = FAISS.from_documents(
-                docs, embeddings, normalize_L2=True)  # docs 为Document列表
-            torch_gc()
+        vector_store = load_vector_store(self.kb_name,
+                                         embeddings=embeddings,
+                                         tick=_VECTOR_STORE_TICKS.get(self.kb_name, 0))
+        vector_store.add_documents(docs)
+        torch_gc()
         vector_store.save_local(self.vs_path)
         refresh_vs_cache(self.kb_name)
 
     def do_delete_doc(self,
                       kb_file: KnowledgeFile):
         embeddings = self._load_embeddings()
-        if os.path.exists(self.vs_path) and "index.faiss" in os.listdir(self.vs_path):
-            vector_store = FAISS.load_local(self.vs_path, embeddings, normalize_L2=True)
-            ids = [k for k, v in vector_store.docstore._dict.items() if v.metadata["source"] == kb_file.filepath]
-            if len(ids) == 0:
-                return None
-            vector_store.delete(ids)
-            vector_store.save_local(self.vs_path)
-            refresh_vs_cache(self.kb_name)
-            return True
-        else:
+        vector_store = load_vector_store(self.kb_name,
+                                         embeddings=embeddings,
+                                         tick=_VECTOR_STORE_TICKS.get(self.kb_name, 0))
+
+        ids = [k for k, v in vector_store.docstore._dict.items() if v.metadata["source"] == kb_file.filepath]
+        if len(ids) == 0:
             return None
 
+        vector_store.delete(ids)
+        vector_store.save_local(self.vs_path)
+        refresh_vs_cache(self.kb_name)
+
+        return True
+
     def do_clear_vs(self):
         shutil.rmtree(self.vs_path)
         os.makedirs(self.vs_path)
+        refresh_vs_cache(self.kb_name)
 
     def exist_doc(self, file_name: str):
         if super().exist_doc(file_name):
diff --git a/tests/api/test_kb_api.py b/tests/api/test_kb_api.py
index c09d57f..5a8b97d 100644
--- a/tests/api/test_kb_api.py
+++ b/tests/api/test_kb_api.py
@@ -8,6 +8,7 @@ root_path = Path(__file__).parent.parent.parent
 sys.path.append(str(root_path))
 from configs.server_config import api_address
 from configs.model_config import VECTOR_SEARCH_TOP_K
+from server.knowledge_base.utils import get_kb_path
 
 from pprint import pprint
 
@@ -22,8 +23,11 @@ test_files = {
 
 
 def test_delete_kb_before(api="/knowledge_base/delete_knowledge_base"):
+    if not Path(get_kb_path(kb)).exists():
+        return
+
     url = api_base_url + api
-    print("\n删除知识库")
+    print("\n测试知识库存在，需要删除")
     r = requests.post(url, json=kb)
     data = r.json()
     pprint(data)