diff --git a/src/promptflow-core/promptflow/core/_serving/v1/blueprint/static_web_blueprint.py b/src/promptflow-core/promptflow/core/_serving/v1/blueprint/static_web_blueprint.py
index dd9cd54a5da..5a7295ace9b 100644
--- a/src/promptflow-core/promptflow/core/_serving/v1/blueprint/static_web_blueprint.py
+++ b/src/promptflow-core/promptflow/core/_serving/v1/blueprint/static_web_blueprint.py
@@ -2,6 +2,7 @@
 # Copyright (c) Microsoft Corporation. All rights reserved.
 # ---------------------------------------------------------
 
+import os
 from pathlib import Path
 
 import flask