diff --git a/paddle/operators/gather.h b/paddle/operators/gather.h
index 8b021565450a7f2ac80a32fd4fc8cb11fd29e54a..0c73717d38aca9f3430e66cafc3ecccdd2eec776 100644
--- a/paddle/operators/gather.h
+++ b/paddle/operators/gather.h
@@ -20,13 +20,10 @@ limitations under the License. */
 #include "paddle/framework/tensor.h"
 #include "paddle/platform/place.h"
 
-using paddle::framework::Tensor;
-using paddle::framework::DDim;
-
 namespace paddle {
 namespace operators {
 
-/* Implementation of CPU copy */
+// Implementation of CPU copy
 template <typename T>
 void CPUGather(const T* params, const int* indices, const int slice_size,
                const int index_size, T* output) {
@@ -34,15 +31,11 @@ void CPUGather(const T* params, const int* indices, const int slice_size,
 
   for (size_t i = 0; i < index_size; ++i) {
     int index_ = indices[i];
-    // copy src[index_] to output[i]
     memcpy(output + i * slice_size, params + index_ * slice_size, slice_bytes);
   }
 }
 
-/* Implementation of GPU copy:
-  I suppose the GPUDevice& d, contains gpu_id and thread_id
-  d = cuda_stream(gpu_id_, stream_id_);
-*/
+// Implementation of GPU copy:
 template <typename T>
 void GPUGather(const T* src, const int* index, const int slice_size,
                const int index_size, T* output);
@@ -62,7 +55,7 @@ void Gather(const platform::Place& place, const paddle::framework::Tensor* src,
   int index_size = index->dims()[0];
 
   auto src_dims = src->dims();
-  DDim output_dims(src_dims);
+  paddle::framework::DDim output_dims(src_dims);
   output_dims[0] = index_size;
 
   // slice size
@@ -73,13 +66,6 @@ void Gather(const platform::Place& place, const paddle::framework::Tensor* src,
   if (platform::is_cpu_place(place)) {
     CPUGather<T>(src->data<T>(), index->data<int>(), slice_size, index_size,
                  output->data<T>());
-  } else {
-    // init for GPU
-    // output_arr = output->mutable_data<T>(output_dims, platform::GPUPlace());
-    // how to specialize device??
-    // GPUGather(
-    //    d, src->data(), index->data(), slice_size,
-    //    new_tensor->mutable_data());
   }
 }
 
diff --git a/paddle/operators/gather_test.cc b/paddle/operators/gather_test.cc
index 5d84b7b5f30e0d838896bb16b39e26d24bd916c1..5de748ec461e4b1a34b75b57c9cd7d5bc9326059 100644
--- a/paddle/operators/gather_test.cc
+++ b/paddle/operators/gather_test.cc
@@ -29,7 +29,6 @@ TEST(Gather, GatherData) {
   Tensor* src = new Tensor();
   Tensor* index = new Tensor();
   Tensor* output = new Tensor();
-  // src.Resize(make_ddim({3, 4}));
 
   int* p_src = nullptr;
   int* p_index = nullptr;
@@ -40,7 +39,6 @@ TEST(Gather, GatherData) {
   p_index[0] = 1;
   p_index[1] = 0;
 
-  // gather
   int* p_output = output->mutable_data<int>(make_ddim({2, 4}), CPUPlace());
 
   Gather<int>(CPUPlace(), src, index, output);