diff --git a/paddle/framework/eigen.h b/paddle/framework/eigen.h
index cd87b042df8557b763e3b40873412c1c038b06ee..f5865635bea4d28e32108bd389699b74b8fd4b17 100644
--- a/paddle/framework/eigen.h
+++ b/paddle/framework/eigen.h
@@ -23,7 +23,7 @@ namespace framework {
 // EigenDim converts paddle::platform::DDim into Eigen::DSizes.
 template <int D>
 struct EigenDim {
-  typedef Eigen::DSizes<Eigen::DenseIndex, D> Type;
+  using Type = Eigen::DSizes<Eigen::DenseIndex, D>;
 
   static Type From(const DDim& dims) {
     PADDLE_ENFORCE(arity(dims) == D, "D must match arity(DDim)");
@@ -69,12 +69,23 @@ struct EigenVector {
   using ConstType =
       Eigen::TensorMap<Eigen::Tensor<const T, 1, Eigen::RowMajor, IndexType>,
                        Eigen::Aligned>;
-
+  // From is to transfer a one dimension Tensor into a one dimension EigenVector
   static Type From(Tensor& tensor) { return EigenTensor<T, 1>::From(tensor); }
 
+  // Flatten is to reshape a Tensor into a one dimension EigenVector
+  static Type Flatten(Tensor& tensor) {
+    return EigenTensor<T, 1>::From(
+        tensor, make_ddim({static_cast<int>(product(tensor.dims_))}));
+  }
+
   static ConstType From(const Tensor& tensor) {
     return EigenTensor<T, 1>::From(tensor);
   }
+
+  static ConstType Flatten(const Tensor& tensor) {
+    return EigenTensor<T, 1>::From(
+        tensor, make_ddim({static_cast<int>(product(tensor.dims_))}));
+  }
 };
 
 // Interpret paddle::platform::Tensor as EigenMatrix and EigenConstMatrix.
diff --git a/paddle/framework/eigen_test.cc b/paddle/framework/eigen_test.cc
index 23eec7533f0ed5055648e13f74a8fe55745f2f30..eca2dce60e73407d15ff046b32416a0c06011ee1 100644
--- a/paddle/framework/eigen_test.cc
+++ b/paddle/framework/eigen_test.cc
@@ -32,6 +32,10 @@ TEST(Eigen, Tensor) {
   }
 
   EigenTensor<float, 3>::Type et = EigenTensor<float, 3>::From(t);
+
+  for (int i = 0; i < 1 * 2 * 3; i++) {
+    EXPECT_EQ(et(i), i);
+  }
   // TODO: check the content of et.
 }
 
@@ -39,5 +43,5 @@ TEST(Eigen, Vector) {}
 
 TEST(Eigen, Matrix) {}
 
-}  // namespace platform
+}  // namespace framework
 }  // namespace paddle
diff --git a/paddle/operators/add_op.h b/paddle/operators/add_op.h
index e7c106a23ffe34baec179f58efa67943a6164a23..39d54a63bd16cdafeec1cfcd86ef5d142382e880 100644
--- a/paddle/operators/add_op.h
+++ b/paddle/operators/add_op.h
@@ -30,9 +30,10 @@ public:
 
     output->mutable_data<T>(context.GetPlace());
 
-    framework::EigenVector<T>::From(*output).device(
+    framework::EigenVector<T>::Flatten(*output).device(
         *(context.GetEigenDevice<Place>())) =
-        framework::EigenVector<T>(*input0) + framework::EigenVector<T>(*input1);
+        framework::EigenVector<T>::Flatten(input0) +
+        framework::EigenVector<T>::Flatten(input1);
   }
 };