diff --git a/python/paddle/fluid/imperative/nn.py b/python/paddle/fluid/imperative/nn.py
index 337a463041b09f13fc2ebb4fff3ee1edbd8fded2..95b59487661313e51af8250b819db2b980ab741f 100644
--- a/python/paddle/fluid/imperative/nn.py
+++ b/python/paddle/fluid/imperative/nn.py
@@ -221,13 +221,10 @@ class FC(layers.Layer):
         from ..layer_helper import LayerHelper
         self._helper = LayerHelper(
             'FC', param_attr=param_attr, act=act, name=name)
-        self._bias_attr = bias_attr
+        self._bias_attr = bias_attr if bias_attr else ParamAttr()
 
     def parameters(self):
-        if self._bias_attr:
-            return [self._w, self._b]
-        else:
-            return [self._w]
+        return [self._w, self._b]
 
     def _build_once(self, input):
         input_shape = input.shape
@@ -264,10 +261,11 @@ class FC(layers.Layer):
         # add bias
         size = list(out.shape[1:])
         if not self._built:
-            self._b = self._layer.create_parameter(
+            self._b = self._helper.create_parameter(
                 attr=self._bias_attr, shape=size, dtype=out.dtype, is_bias=True)
-        bias_out = self.create_variable_for_type_inference(dtype=out.dtype)
-        self.append_op(
+        bias_out = self._helper.create_variable_for_type_inference(
+            dtype=out.dtype)
+        self._helper.append_op(
             type='elementwise_add',
             inputs={'X': [out],
                     'Y': [self._b]},
diff --git a/python/paddle/fluid/layer_helper.py b/python/paddle/fluid/layer_helper.py
index ea9953f5814207c569e799c2ffa11758e31699aa..e0fd44ae31e3e66adfb8d5dd8a21051c48d24afa 100644
--- a/python/paddle/fluid/layer_helper.py
+++ b/python/paddle/fluid/layer_helper.py
@@ -405,8 +405,7 @@ class LayerHelper(object):
         """
         size = list(input_var.shape[dim_start:dim_end])
         bias_attr = self.bias_attr
-        if not bias_attr:
-            return input_var
+        assert bias_attr is not None
 
         b = self.create_parameter(
             attr=bias_attr, shape=size, dtype=input_var.dtype, is_bias=True)
diff --git a/python/paddle/fluid/tests/unittests/test_imperative_gan.py b/python/paddle/fluid/tests/unittests/test_imperative_gan.py
index c38906ce6adbf471dfb3faceb5690bf67793ff2d..410c75026bbed2198bebe8907a862579a0307ff0 100644
--- a/python/paddle/fluid/tests/unittests/test_imperative_gan.py
+++ b/python/paddle/fluid/tests/unittests/test_imperative_gan.py
@@ -121,21 +121,21 @@ class TestImperativeMnist(unittest.TestCase):
             img = np.ones([2, 1], np.float32)
             noise = np.ones([2, 2], np.float32)
             exe.run(startup)
-            d_loss_val = exe.run(discriminate_p,
-                                 feed={'img': img,
-                                       'noise': noise},
-                                 fetch_list=[d_loss])[0]
-            g_loss_val = exe.run(generate_p,
-                                 feed={'noise': noise},
-                                 fetch_list=[g_loss])[0]
+            static_d_loss = exe.run(discriminate_p,
+                                    feed={'img': img,
+                                          'noise': noise},
+                                    fetch_list=[d_loss])[0]
+            static_g_loss = exe.run(generate_p,
+                                    feed={'noise': noise},
+                                    fetch_list=[g_loss])[0]
+
+            # generate_p contains all parameters needed.
             for param in generate_p.global_block().all_parameters():
                 static_params[param.name] = np.array(
                     scope.find_var(param.name).get_tensor())
                 sys.stderr.write(
                     'static_param_loss: %s: %s\n' %
                     (param.name, np.sum(static_params[param.name])))
-            sys.stderr.write('d_loss %s, g_loss: %s\n' %
-                             (d_loss_val, g_loss_val))
 
         dy_params = dict()
         with fluid.imperative.guard():
@@ -181,8 +181,14 @@ class TestImperativeMnist(unittest.TestCase):
                 dy_params[p.name] = p._numpy()
                 sys.stderr.write('dy_param_loss: %s: %s\n' %
                                  (p.name, np.sum(dy_params[p.name])))
-            sys.stderr.write('dy_d_loss: %s, dy_g_loss: %s\n' %
-                             (d_loss._numpy(), g_loss._numpy()))
+
+            dy_g_loss = g_loss._numpy()
+            dy_d_loss = d_loss._numpy()
+
+        self.assertEqual(dy_g_loss, static_g_loss)
+        self.assertEqual(dy_d_loss, static_d_loss)
+        for k, v in six.iteritems(dy_params):
+            self.assertTrue(np.allclose(v, static_params[k]))
 
 
 if __name__ == '__main__':