diff --git a/swift/llm/template/base.py b/swift/llm/template/base.py
index e9224ee82..0b9091195 100644
--- a/swift/llm/template/base.py
+++ b/swift/llm/template/base.py
@@ -181,7 +181,8 @@ def _kto_encode(self, inputs: StdTemplateInputs) -> Dict[str, Any]:
 
     def _seq_cls_encode(self, inputs: StdTemplateInputs) -> Dict[str, Any]:
         encoded = self._encode(inputs)
-        encoded['labels'] = int(inputs.label)
+        if inputs.label is not None:
+            encoded['labels'] = int(inputs.label)
         return encoded
 
     def encode(self,