diff --git a/neural_compressor/adaptor/ox_utils/operators/attention.py b/neural_compressor/adaptor/ox_utils/operators/attention.py
index 9e12f57b3a2..840470b194a 100644
--- a/neural_compressor/adaptor/ox_utils/operators/attention.py
+++ b/neural_compressor/adaptor/ox_utils/operators/attention.py
@@ -60,8 +60,7 @@ def convert(self, convert_format):
         inputs.extend(quantized_name)
         inputs.append(node.input[2])
         inputs.extend(scale)
-        if len(node.input) > 3:
-            inputs.append(node.input[3])
+        inputs.append(node.input[3] if len(node.input) > 3 else "")
         inputs.extend(zp)
         if len(node.input) > 4:
             inputs.append(node.input[4])
@@ -74,4 +73,4 @@ def convert(self, convert_format):
                                                  node.name, **kwargs)
         self.quantizer.new_nodes.append(qattention_node)
 
-        self.quantizer.remove_nodes.append(node)
\ No newline at end of file
+        self.quantizer.remove_nodes.append(node)