diff --git a/api/tests/unit_tests/services/test_conversation_variable_updater.py b/api/tests/unit_tests/services/test_conversation_variable_updater.py
index 157424a2a7..20f7caa78e 100644
--- a/api/tests/unit_tests/services/test_conversation_variable_updater.py
+++ b/api/tests/unit_tests/services/test_conversation_variable_updater.py
@@ -3,7 +3,7 @@ from unittest.mock import MagicMock
 
 import pytest
 
-from core.variables.variables import StringVariable
+from dify_graph.variables import StringVariable
 from services.conversation_variable_updater import ConversationVariableNotFoundError, ConversationVariableUpdater