diff --git a/paddle/fluid/eager/backward.cc b/paddle/fluid/eager/backward.cc
index 0477c5d5f90d8bc61caf0f2a02c9f44d9e73ad64..dd310757956c037290edccbc344012e5d1a00695 100644
--- a/paddle/fluid/eager/backward.cc
+++ b/paddle/fluid/eager/backward.cc
@@ -141,6 +141,7 @@ std::vector<paddle::Tensor> RunBackward(
   std::deque<GradNodeBase*> orig_queue;
   std::unordered_map<GradNodeBase*, std::unique_ptr<GradTensorHolder>>
       node_input_buffers_dict;
+  std::unordered_set<GradNodeBase*> visited;
   for (size_t i = 0; i < tensors.size(); i++) {
     const paddle::Tensor& tensor = tensors[i];
 
@@ -215,6 +216,10 @@ std::vector<paddle::Tensor> RunBackward(
     }
 
     // Prepare queue, potential startup_nodes
+    if (visited.count(grad_node)) {
+      continue;
+    }
+    visited.insert(grad_node);
     queue.push_back(grad_node);
   }
 
diff --git a/paddle/fluid/eager/pylayer/py_layer_node.cc b/paddle/fluid/eager/pylayer/py_layer_node.cc
index 4dac92b63dd8e31b260a269e80481596264d9ad1..3f88c22148c105cde2e14b568d35eabc0034b42a 100644
--- a/paddle/fluid/eager/pylayer/py_layer_node.cc
+++ b/paddle/fluid/eager/pylayer/py_layer_node.cc
@@ -163,7 +163,7 @@ GradNodePyLayer::operator()(
                 {paddle::pybind::UnSafeGetTensorFromPyObject(obj)});
           } else if (obj == Py_None) {
             VLOG(4) << "Got None for Tensor with pos: " << i;
-            grad_out.push_back({});
+            grad_out.push_back({paddle::Tensor()});
           } else {
             PADDLE_THROW(phi::errors::InvalidArgument(
                 "We can only support Tensor or None for backward output, "