diff --git a/apps/application/flow/step_node/ai_chat_step_node/impl/base_chat_node.py b/apps/application/flow/step_node/ai_chat_step_node/impl/base_chat_node.py
index 2db06fe62..9f64a65ad 100644
--- a/apps/application/flow/step_node/ai_chat_step_node/impl/base_chat_node.py
+++ b/apps/application/flow/step_node/ai_chat_step_node/impl/base_chat_node.py
@@ -271,6 +271,9 @@ class BaseChatNode(IChatNode):
 
         mcp_servers_config = {}
 
+        # 迁移过来mcp_source是None
+        if mcp_source is None:
+            mcp_source = 'custom'
         if mcp_enable:
             if mcp_source == 'custom' and mcp_servers is not None and '"stdio"' not in mcp_servers:
                 mcp_servers_config = json.loads(mcp_servers)