diff --git a/api/core/workflow/nodes/knowledge_retrieval/knowledge_retrieval_node.py b/api/core/workflow/nodes/knowledge_retrieval/knowledge_retrieval_node.py
index ea370c908b9844..e9aa65540117df 100644
--- a/api/core/workflow/nodes/knowledge_retrieval/knowledge_retrieval_node.py
+++ b/api/core/workflow/nodes/knowledge_retrieval/knowledge_retrieval_node.py
@@ -49,6 +49,12 @@ def _run(self, variable_pool: VariablePool) -> NodeRunResult:
         variables = {
             'query': query
         }
+        if not query:
+            return NodeRunResult(
+                status=WorkflowNodeExecutionStatus.FAILED,
+                inputs=variables,
+                error="Query is required."
+            )
         # retrieve knowledge
         try:
             results = self._fetch_dataset_retriever(