diff --git a/paddle/fluid/inference/tensorrt/convert/ut_helper.h b/paddle/fluid/inference/tensorrt/convert/ut_helper.h
index a4ab111eb4bc0a982e5f32fd496b96793048e1ba..39529cc2c799212f91107b1b86dd2c8c3642b6da 100644
--- a/paddle/fluid/inference/tensorrt/convert/ut_helper.h
+++ b/paddle/fluid/inference/tensorrt/convert/ut_helper.h
@@ -162,7 +162,8 @@ class TRTConvertValidation {
 
       size_t fluid_out_size = fluid_out.size();
       if (if_add_batch_ == true) {
-        fluid_out_size = batch_size * (tensor->dims().size() / max_batch_size_);
+        fluid_out_size =
+            batch_size * (framework::product(tensor->dims()) / max_batch_size_);
       }
       // Compare two output
       ASSERT_FALSE(fluid_out.empty());