diff --git a/paddle/fluid/API.spec b/paddle/fluid/API.spec
index d6e65f3e0425e6b614a49c3d6c1f1651da4bf880..97832627ea667c288736f7d4c4f2d80b58fd4b88 100755
--- a/paddle/fluid/API.spec
+++ b/paddle/fluid/API.spec
@@ -567,7 +567,7 @@ paddle.fluid.contrib.BasicLSTMUnit.sublayers (ArgSpec(args=['self', 'include_sub
 paddle.fluid.contrib.BasicLSTMUnit.train (ArgSpec(args=['self'], varargs=None, keywords=None, defaults=None), ('document', '6adf97f83acf6453d4a6a4b1070f3754'))
 paddle.fluid.contrib.basic_lstm (ArgSpec(args=['input', 'init_hidden', 'init_cell', 'hidden_size', 'num_layers', 'sequence_length', 'dropout_prob', 'bidirectional', 'batch_first', 'param_attr', 'bias_attr', 'gate_activation', 'activation', 'forget_bias', 'dtype', 'name'], varargs=None, keywords=None, defaults=(1, None, 0.0, False, True, None, None, None, None, 1.0, 'float32', 'basic_lstm')), ('document', 'fe4d0c3c55a162b8cfe10b05fabb7ce4'))
 paddle.fluid.contrib.ctr_metric_bundle (ArgSpec(args=['input', 'label'], varargs=None, keywords=None, defaults=None), ('document', 'b68d12366896c41065fc3738393da2aa'))
-paddle.fluid.data (ArgSpec(args=['name', 'shape', 'dtype', 'lod_level'], varargs=None, keywords=None, defaults=('float32', 0)), ('document', '28ee6b35836449f44ce53467f0616137'))
+paddle.fluid.data (ArgSpec(args=['name', 'shape', 'dtype', 'lod_level'], varargs=None, keywords=None, defaults=('float32', 0)), ('document', 'a44fce9b5c8919bf5937a1cc0fe484ca'))
 paddle.fluid.dygraph.Layer ('paddle.fluid.dygraph.layers.Layer', ('document', 'a889d5affd734ede273e94d4257163ab'))
 paddle.fluid.dygraph.Layer.__init__ (ArgSpec(args=['self', 'name_scope', 'dtype'], varargs=None, keywords=None, defaults=(VarType.FP32,)), ('document', '6adf97f83acf6453d4a6a4b1070f3754'))
 paddle.fluid.dygraph.Layer.add_parameter (ArgSpec(args=['self', 'name', 'parameter'], varargs=None, keywords=None, defaults=None), ('document', 'f35ab374c7d5165c3daf3bd64a5a2ec1'))
diff --git a/python/paddle/fluid/data.py b/python/paddle/fluid/data.py
index b90a681ed8e1bb3de0e4a9825a5af17eb0eaf457..26f24f029cd32c58302b551dbdf4fa36c221fc10 100644
--- a/python/paddle/fluid/data.py
+++ b/python/paddle/fluid/data.py
@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import numpy as np
+import six
 
 from . import core
 from .layer_helper import LayerHelper
@@ -41,7 +42,9 @@ def data(name, shape, dtype='float32', lod_level=0):
     Args:
        name (str): The name/alias of the variable, see :ref:`api_guide_Name`
            for more details.
-       shape (list|tuple): List|Tuple of integers declaring the shape.
+       shape (list|tuple): List|Tuple of integers declaring the shape. You can
+           set "None" at a dimension to indicate the dimension can be of any
+           size. For example, it is useful to set changable batch size as "None" 
        dtype (np.dtype|VarType|str, optional): The type of the data. Supported
            dtype: bool, float16, float32, float64, int8, int16, int32, int64,
            uint8. Default: float32
@@ -62,10 +65,10 @@ def data(name, shape, dtype='float32', lod_level=0):
           # User can only feed data of the same shape to x
           x = fluid.data(name='x', shape=[3, 2, 1], dtype='float32')
 
-          # Creates a variable with changable batch size -1.
+          # Creates a variable with changable batch size.
           # Users can feed data of any batch size into y,
           # but size of each data sample has to be [2, 1]
-          y = fluid.data(name='y', shape=[-1, 2, 1], dtype='float32')
+          y = fluid.data(name='y', shape=[None, 2, 1], dtype='float32')
 
           z = x + y
 
@@ -86,6 +89,11 @@ def data(name, shape, dtype='float32', lod_level=0):
 
     """
     helper = LayerHelper('data', **locals())
+    shape = list(shape)
+    for i in six.moves.range(len(shape)):
+        if shape[i] is None:
+            shape[i] = -1
+
     return helper.create_global_variable(
         name=name,
         shape=shape,
diff --git a/python/paddle/fluid/executor.py b/python/paddle/fluid/executor.py
index 460f1eae741b7c61a542453cb5eef95fa1f8202b..6e8d07e2836f382f7482e5e97d9db1d45c411419 100644
--- a/python/paddle/fluid/executor.py
+++ b/python/paddle/fluid/executor.py
@@ -22,6 +22,7 @@ import warnings
 import numpy as np
 from .wrapped_decorator import signature_safe_contextmanager
 import six
+from .data_feeder import convert_dtype
 from .framework import Program, default_main_program, Variable, convert_np_dtype_to_dtype_
 from . import core
 from . import compiler
@@ -204,13 +205,18 @@ def check_feed_shape_type(var, feed):
     """
     if var.desc.need_check_feed():
         if not dimension_is_compatible_with(feed.shape(), var.shape):
-            raise ValueError('Cannot feed value of shape %r for Variable %r, '
-                             'which has shape %r' %
-                             (feed.shape, var.name, var.shape))
+            raise ValueError(
+                'The feeded Variable %r should have dimensions = %d, shape = '
+                '%r, but received feeded shape %r' %
+                (var.name, len(var.shape), var.shape, feed.shape()))
         if not dtype_is_compatible_with(feed._dtype(), var.dtype):
-            raise ValueError('Cannot feed value of type %r for Variable %r, '
-                             'which has type %r' %
-                             (feed._dtype(), var.name, var.dtype))
+            var_dtype_format = convert_dtype(var.dtype) if isinstance(
+                var.dtype, core.VarDesc.VarType) else var.dtype
+            feed_dtype_format = convert_dtype(feed._dtype()) if isinstance(
+                feed._dtype(), core.VarDesc.VarType) else feed._dtype()
+            raise ValueError(
+                'The data type of feeded Variable %r must be %r, but received %r'
+                % (var.name, var_dtype_format, feed_dtype_format))
     return True
 
 
diff --git a/python/paddle/fluid/tests/unittests/test_feed_data_check_shape_type.py b/python/paddle/fluid/tests/unittests/test_feed_data_check_shape_type.py
index 2489ae8e266df95d8b96d2dcb608cff5d2764338..6cb483992927363acb990cf2f72d625d6c2d3b5f 100644
--- a/python/paddle/fluid/tests/unittests/test_feed_data_check_shape_type.py
+++ b/python/paddle/fluid/tests/unittests/test_feed_data_check_shape_type.py
@@ -21,6 +21,7 @@ import paddle
 import paddle.fluid as fluid
 import paddle.fluid.compiler as compiler
 import paddle.fluid.core as core
+import six
 import unittest
 
 os.environ['CPU_NUM'] = str(4)
@@ -65,25 +66,64 @@ class TestFeedData(unittest.TestCase):
         return in_data, label, loss
 
     def test(self):
-        for use_cuda in [True, False] if core.is_compiled_with_cuda(
-        ) else [False]:
+        for use_cuda in [True,
+                         False] if core.is_compiled_with_cuda() else [False]:
             for use_parallel_executor in [False, True]:
                 print('Test Parameters:'),
                 print({
                     'use_cuda': use_cuda,
                     'use_parallel_executor': use_parallel_executor,
                 })
+                # Test feeding without error
                 self._test_feed_data_match_shape_type(use_cuda,
                                                       use_parallel_executor)
                 self._test_feed_data_contains_neg_one(use_cuda,
                                                       use_parallel_executor)
-                with self.assertRaises(ValueError):
+
+                # Test exception message when feeding with error 
+                batch_size = self._get_batch_size(use_cuda,
+                                                  use_parallel_executor)
+                if six.PY2:
+                    in_shape_tuple = (long(-1), long(3), long(4), long(8))
+                    feed_shape_list = [
+                        long(batch_size), long(3), long(4), long(5)
+                    ]
+                else:
+                    in_shape_tuple = (-1, 3, 4, 8)
+                    feed_shape_list = [batch_size, 3, 4, 5]
+
+                with self.assertRaises(ValueError) as shape_mismatch_err:
                     self._test_feed_data_shape_mismatch(use_cuda,
                                                         use_parallel_executor)
+                self.assertEqual(
+                    str(shape_mismatch_err.exception),
+                    "The feeded Variable %r should have dimensions = %r, "
+                    "shape = %r, but received feeded shape %r" %
+                    (u'data', len(in_shape_tuple), in_shape_tuple,
+                     feed_shape_list))
+
+                with self.assertRaises(ValueError) as dtype_mismatch_err:
+                    self._test_feed_data_dtype_mismatch(use_cuda,
+                                                        use_parallel_executor)
+                self.assertEqual(
+                    str(dtype_mismatch_err.exception),
+                    "The data type of feeded Variable %r must be 'int64', but "
+                    "received 'float64'" % (u'label'))
+
+    def _test_feed_data_dtype_mismatch(self, use_cuda, use_parallel_executor):
+        batch_size = self._get_batch_size(use_cuda, use_parallel_executor)
+        in_size = [batch_size, 3, 4, 5]
+        feed_in_data = np.random.uniform(
+            size=[batch_size, 3, 4, 5]).astype(np.float32)
+        label_size = [batch_size, 1]
+        feed_label = np.random.randint(
+            low=0, high=self.class_num, size=[batch_size, 1]).astype(np.float64)
+        self._feed_data_in_executor(in_size, label_size, feed_in_data,
+                                    feed_label, use_cuda, use_parallel_executor)
 
     def _test_feed_data_shape_mismatch(self, use_cuda, use_parallel_executor):
         batch_size = self._get_batch_size(use_cuda, use_parallel_executor)
-        in_size = [-1, 3, 4, 8]
+        in_size = [None, 3, 4, 8]
         feed_in_data = np.random.uniform(
             size=[batch_size, 3, 4, 5]).astype(np.float32)
         label_size = [-1, 1]
@@ -97,7 +137,7 @@ class TestFeedData(unittest.TestCase):
         in_size = [-1, 3, 4, 5]
         feed_in_data = np.random.uniform(
             size=[batch_size, 3, 4, 5]).astype(np.float32)
-        label_size = (-1, 1)
+        label_size = (None, 1)
         feed_label = np.random.randint(
             low=0, high=self.class_num, size=[batch_size, 1]).astype(np.int64)
         self._feed_data_in_executor(in_size, label_size, feed_in_data,