diff --git a/paddle/operators/conv_transpose_op.h b/paddle/operators/conv_transpose_op.h
index 0aae000dc417c76b85c619d1f4a05e9666d9aee6..1171b0435fd2b1abe541043e8283a8fc09dc13c7 100644
--- a/paddle/operators/conv_transpose_op.h
+++ b/paddle/operators/conv_transpose_op.h
@@ -225,7 +225,6 @@ class GemmConvTransposeGradKernel : public framework::OpKernel<T> {
 
       if (input_grad) {
         input_grad->mutable_data<T>(context.GetPlace());
-        // set_zero is unnecessary, math::matmul will reset input_grad.
       }
       if (filter_grad) {  // filter size (m, c, k_h, k_w)
         filter_grad->mutable_data<T>(context.GetPlace());