diff --git a/paddle/fluid/API.spec b/paddle/fluid/API.spec
index b72c1eb997e7a2937d3bec5a775cb46c27f7892c..37153f7174159b2f7c8cca5a7006c6013def0e53 100755
--- a/paddle/fluid/API.spec
+++ b/paddle/fluid/API.spec
@@ -302,7 +302,7 @@ paddle.fluid.layers.pixel_shuffle (ArgSpec(args=['x', 'upscale_factor'], varargs
 paddle.fluid.layers.fsp_matrix (ArgSpec(args=['x', 'y'], varargs=None, keywords=None, defaults=None), ('document', 'd803767ef4fb885013a28c98634e0bc4'))
 paddle.fluid.layers.continuous_value_model (ArgSpec(args=['input', 'cvm', 'use_cvm'], varargs=None, keywords=None, defaults=(True,)), ('document', 'c03490ffaa1b78258747157c313db4cd'))
 paddle.fluid.layers.where (ArgSpec(args=['condition'], varargs=None, keywords=None, defaults=None), ('document', 'b1e1487760295e1ff55307b880a99e18'))
-paddle.fluid.layers.sign (ArgSpec(args=['x'], varargs=None, keywords=None, defaults=None), ('document', 'fa2f457a81714430c5677c2d68744728'))
+paddle.fluid.layers.sign (ArgSpec(args=['x'], varargs=None, keywords=None, defaults=None), ('document', 'b56afe9ae3fc553c95d907fd7ef6c314'))
 paddle.fluid.layers.deformable_conv (ArgSpec(args=['input', 'offset', 'mask', 'num_filters', 'filter_size', 'stride', 'padding', 'dilation', 'groups', 'deformable_groups', 'im2col_step', 'param_attr', 'bias_attr', 'modulated', 'name'], varargs=None, keywords=None, defaults=(1, 0, 1, None, None, None, None, None, True, None)), ('document', '9b9c9d1282f994ccd4538201e0b6856f'))
 paddle.fluid.layers.unfold (ArgSpec(args=['x', 'kernel_sizes', 'strides', 'paddings', 'dilations', 'name'], varargs=None, keywords=None, defaults=(1, 0, 1, None)), ('document', '3f884662ad443d9ecc2b3734b4f61ad6'))
 paddle.fluid.layers.deformable_roi_pooling (ArgSpec(args=['input', 'rois', 'trans', 'no_trans', 'spatial_scale', 'group_size', 'pooled_height', 'pooled_width', 'part_size', 'sample_per_part', 'trans_std', 'position_sensitive', 'name'], varargs=None, keywords=None, defaults=(False, 1.0, [1, 1], 1, 1, None, 1, 0.1, False, None)), ('document', '47c5d1c890b36fa00ff3285c9398f613'))
diff --git a/python/paddle/fluid/layers/nn.py b/python/paddle/fluid/layers/nn.py
index bb12a20a9112787b8a7280215bca9a1de8aa7164..627e2cac82eae1638a9f970e22ad861f9d4aa722 100755
--- a/python/paddle/fluid/layers/nn.py
+++ b/python/paddle/fluid/layers/nn.py
@@ -14881,14 +14881,24 @@ def sign(x):
           import numpy as np
 
           # [1, 0, -1]
-          data = fluid.layers.sign(np.array([3, 0, -2], dtype='int32')) 
+          data = fluid.layers.sign(np.array([3, 0, -2], dtype='float32')) 
 
     """
 
     helper = LayerHelper("sign", **locals())
 
     if not isinstance(x, Variable):
-        x = assign(x)
+        if isinstance(x, np.ndarray):
+            x = assign(x)
+        else:
+            raise TypeError(
+                "The type of 'x' in sign_op must be Variable or numpy.ndarray, but received %s."
+                % (type(x)))
+
+    if convert_dtype(x.dtype) not in ['float32', 'float64']:
+        raise TypeError(
+            "The data type of 'x' in sign_op must be float32 or float64, but received %s."
+            % (convert_dtype(x.dtype)))
 
     out = helper.create_variable_for_type_inference(dtype=x.dtype)
 
diff --git a/python/paddle/fluid/tests/unittests/test_sign_op.py b/python/paddle/fluid/tests/unittests/test_sign_op.py
index 85a9d9cae47c2b0942da0e0d962d4512af1566c0..00ac43b9ba569c87a48d8fe3a62551b653249c73 100644
--- a/python/paddle/fluid/tests/unittests/test_sign_op.py
+++ b/python/paddle/fluid/tests/unittests/test_sign_op.py
@@ -17,6 +17,8 @@ from __future__ import print_function
 import unittest
 import numpy as np
 from op_test import OpTest
+import paddle.fluid as fluid
+from paddle.fluid import Program, program_guard
 
 
 class TestSignOp(OpTest):
@@ -34,5 +36,17 @@ class TestSignOp(OpTest):
         self.check_grad(['X'], 'Out')
 
 
+class TestSignOpError(OpTest):
+    def test_errors(self):
+        with program_guard(Program(), Program()):
+            # The input type of sign_op must be Variable or numpy.ndarray.
+            input1 = 12
+            self.assertRaises(TypeError, fluid.layers.sign, input1)
+            # The input dtype of sign_op must be float32, float64.
+            input2 = fluid.layers.data(
+                name='input2', shape=[12, 10], dtype="int32")
+            self.assertRaises(TypeError, fluid.layers.sign, input2)
+
+
 if __name__ == "__main__":
     unittest.main()