diff --git a/api/core/model_runtime/model_providers/azure_openai/llm/llm.py b/api/core/model_runtime/model_providers/azure_openai/llm/llm.py
index 2ad2289869bbae..3b9fb52e24ec93 100644
--- a/api/core/model_runtime/model_providers/azure_openai/llm/llm.py
+++ b/api/core/model_runtime/model_providers/azure_openai/llm/llm.py
@@ -420,7 +420,7 @@ def _handle_chat_generate_stream_response(
                 ),
             )
 
-            index += 0
+            index += 1
 
         # calculate num tokens
         prompt_tokens = self._num_tokens_from_messages(credentials, prompt_messages, tools)