diff --git a/paddle/gserver/layers/ConcatenateLayer.cpp b/paddle/gserver/layers/ConcatenateLayer.cpp
index bb6709b8df..a986ec10b4 100644
--- a/paddle/gserver/layers/ConcatenateLayer.cpp
+++ b/paddle/gserver/layers/ConcatenateLayer.cpp
@@ -160,7 +160,9 @@ void ConcatenateLayer2::forward(PassType passType) {
     size_t startCol = projCol_[i].first;
     size_t endCol = projCol_[i].second;
     projOutput_[i].value = output_.value->subColMatrix(startCol, endCol);
-    projOutput_[i].grad = output_.grad->subColMatrix(startCol, endCol);
+    if (output_.grad) {
+      projOutput_[i].grad = output_.grad->subColMatrix(startCol, endCol);
+    }
   }
 
   {
diff --git a/paddle/gserver/layers/SpatialPyramidPoolLayer.cpp b/paddle/gserver/layers/SpatialPyramidPoolLayer.cpp
index 582abf78c8..2fcfc8e1ae 100644
--- a/paddle/gserver/layers/SpatialPyramidPoolLayer.cpp
+++ b/paddle/gserver/layers/SpatialPyramidPoolLayer.cpp
@@ -112,7 +112,9 @@ void SpatialPyramidPoolLayer::forward(PassType passType) {
     size_t startCol = projCol_[i].first;
     size_t endCol = projCol_[i].second;
     projOutput_[i].value = output_.value->subColMatrix(startCol, endCol);
-    projOutput_[i].grad = output_.grad->subColMatrix(startCol, endCol);
+    if (output_.grad) {
+      projOutput_[i].grad = output_.grad->subColMatrix(startCol, endCol);
+    }
   }
   for (size_t i = 0; i < pyramidHeight_; i++) {
     poolProjections_[i]->forward(&getInput(0), &projOutput_[i], passType);