diff --git a/lyrebird/mock/handlers/flow_editor_handler.py b/lyrebird/mock/handlers/flow_editor_handler.py
index 99d3f237..88b5c2f5 100644
--- a/lyrebird/mock/handlers/flow_editor_handler.py
+++ b/lyrebird/mock/handlers/flow_editor_handler.py
@@ -50,7 +50,7 @@ def on_response_handler(self, handler_context):
             handler_context.flow['response']['code'] = 200
         if not handler_context.flow['response'].get('headers'):
             handler_context.flow['response']['headers'] = {}
-        if not handler_context.flow['response'].get('data'):
+        if 'data' not in handler_context.flow['response']:
             if handler_context.response:
                 handler_context.update_response_data2flow()
             else:
diff --git a/lyrebird/mock/handlers/handler_context.py b/lyrebird/mock/handlers/handler_context.py
index 850e317e..3dcdcf78 100644
--- a/lyrebird/mock/handlers/handler_context.py
+++ b/lyrebird/mock/handlers/handler_context.py
@@ -309,8 +309,10 @@ def update_client_resp_time(self):
         resp_data = self.flow['response'].get('data', '')
         if isinstance(resp_data, str):
             self.flow['size'] = len(resp_data.encode())
-        else:
+        elif resp_data:
             self.flow['size'] = len(resp_data)
+        else:
+            self.flow['size'] = 0
 
         self.flow['duration'] = self.server_resp_time - self.client_req_time