diff --git a/paddle/fluid/API.spec b/paddle/fluid/API.spec
index 64f1b3b436c70f8a107706e0d242096ec70deb50..3b73291ca5213422f65245a6b146f500d3af2e57 100644
--- a/paddle/fluid/API.spec
+++ b/paddle/fluid/API.spec
@@ -95,7 +95,7 @@ paddle.fluid.initializer.NumpyArrayInitializer ('paddle.fluid.initializer.NumpyA
 paddle.fluid.initializer.NumpyArrayInitializer.__init__ (ArgSpec(args=['self', 'value'], varargs=None, keywords=None, defaults=None), ('document', '6adf97f83acf6453d4a6a4b1070f3754'))
 paddle.fluid.layers.fc (ArgSpec(args=['input', 'size', 'num_flatten_dims', 'param_attr', 'bias_attr', 'act', 'is_test', 'name'], varargs=None, keywords=None, defaults=(1, None, None, None, False, None)), ('document', '1c74f52549814235077ecc34856a95eb'))
 paddle.fluid.layers.center_loss (ArgSpec(args=['input', 'label', 'num_classes', 'alpha', 'param_attr', 'update_center'], varargs=None, keywords=None, defaults=(True,)), ('document', '7129819d94625c6104054e8187768589'))
-paddle.fluid.layers.embedding (ArgSpec(args=['input', 'size', 'is_sparse', 'is_distributed', 'padding_idx', 'param_attr', 'dtype'], varargs=None, keywords=None, defaults=(False, False, None, None, 'float32')), ('document', '1b4916f765620374ad0fdefe5a352993'))
+paddle.fluid.layers.embedding (ArgSpec(args=['input', 'size', 'is_sparse', 'is_distributed', 'padding_idx', 'param_attr', 'dtype'], varargs=None, keywords=None, defaults=(False, False, None, None, 'float32')), ('document', 'd8e405486a1e4e189b51d6ee28d67b1e'))
 paddle.fluid.layers.dynamic_lstm (ArgSpec(args=['input', 'size', 'h_0', 'c_0', 'param_attr', 'bias_attr', 'use_peepholes', 'is_reverse', 'gate_activation', 'cell_activation', 'candidate_activation', 'dtype', 'name'], varargs=None, keywords=None, defaults=(None, None, None, None, True, False, 'sigmoid', 'tanh', 'tanh', 'float32', None)), ('document', '6d3ee14da70adfa36d85c40b18716ef2'))
 paddle.fluid.layers.dynamic_lstmp (ArgSpec(args=['input', 'size', 'proj_size', 'param_attr', 'bias_attr', 'use_peepholes', 'is_reverse', 'gate_activation', 'cell_activation', 'candidate_activation', 'proj_activation', 'dtype', 'name', 'h_0', 'c_0', 'cell_clip', 'proj_clip'], varargs=None, keywords=None, defaults=(None, None, True, False, 'sigmoid', 'tanh', 'tanh', 'tanh', 'float32', None, None, None, None, None)), ('document', 'c37d51aad655c8a9f9b045c64717320a'))
 paddle.fluid.layers.dynamic_gru (ArgSpec(args=['input', 'size', 'param_attr', 'bias_attr', 'is_reverse', 'gate_activation', 'candidate_activation', 'h_0', 'origin_mode'], varargs=None, keywords=None, defaults=(None, None, False, 'sigmoid', 'tanh', None, False)), ('document', '83617c165827e030636c80486d5de6f3'))
diff --git a/python/paddle/fluid/layers/nn.py b/python/paddle/fluid/layers/nn.py
index babf5fd64e720a66334ae3953e0d248a1e7c8bf8..b269b01ee78e2d651c7f73a4c41dc2a765a4035a 100644
--- a/python/paddle/fluid/layers/nn.py
+++ b/python/paddle/fluid/layers/nn.py
@@ -463,18 +463,20 @@ def embedding(input,
 
     Args:
         input(Variable): Input is a Tensor<int64> Variable, which contains the IDs information.
+            The value of the input IDs should satisfy :math:`0<= id < size[0]`.
         size(tuple|list): The shape of the look up table parameter. It should
             have two elements which indicate the size of the dictionary of
             embeddings and the size of each embedding vector respectively.
         is_sparse(bool): The flag indicating whether to use sparse update.
         is_distributed(bool): Whether to run lookup table from remote parameter server.
-        padding_idx(int|long|None): If :attr:`None`, it makes no effect to lookup.
-            Otherwise the given :attr:`padding_idx` indicates padding the output
-            with zeros whenever lookup encounters it in :attr:`input`. If
-            :math:`padding_idx < 0`, the :attr:`padding_idx` to use in lookup is
-            :math:`size[0] + dim`.
-        param_attr(ParamAttr): Parameters for this layer
-        dtype(np.dtype|core.VarDesc.VarType|str): The type of data : float32, float_16, int etc
+        padding_idx(int|long|None): It will output all-zero padding data whenever
+            lookup encounters :math:`padding\_idx` in Ids. If set :attr:`None`, it makes
+            no effect to output. If :math:`padding\_idx < 0`, the :math:`padding\_idx`
+            will automatically be converted to :math:`size[0] + padding\_idx` to use.
+            Default: None.
+        param_attr(ParamAttr): Parameters for this layer.
+        dtype(np.dtype|core.VarDesc.VarType|str): The dtype refers to the data type of output
+            tensor. It can be float32, float_16, int etc.
 
     Returns:
         Variable: The tensor variable storing the embeddings of the \