diff --git a/python/paddle/fluid/dygraph/base.py b/python/paddle/fluid/dygraph/base.py
index 63f861e38ca462b9a05bc59ca73729a063d0a336..13b09f14556b576de95736a0fd641315742a66d0 100644
--- a/python/paddle/fluid/dygraph/base.py
+++ b/python/paddle/fluid/dygraph/base.py
@@ -22,6 +22,7 @@ from .tracer import Tracer
 __all__ = [
     'enabled',
     'no_grad',
+    'not_support',
     'guard',
     'to_variable',
 ]
@@ -43,6 +44,15 @@ def _switch_tracer_mode_guard_(is_train=True):
         yield
 
 
+def _dygraph_not_support_(func):
+    def __impl__(*args, **kwargs):
+        assert not framework.in_dygraph_mode(
+        ), "We don't support %s in Dygraph mode" % func.__name__
+        return func(*args, **kwargs)
+
+    return __impl__
+
+
 def _no_grad_(func):
     def __impl__(*args, **kwargs):
         with _switch_tracer_mode_guard_(is_train=False):
@@ -52,6 +62,7 @@ def _no_grad_(func):
 
 
 no_grad = wrap_decorator(_no_grad_)
+not_support = wrap_decorator(_dygraph_not_support_)
 
 
 @signature_safe_contextmanager
diff --git a/python/paddle/fluid/tests/unittests/test_imperative_ocr_attention_model.py b/python/paddle/fluid/tests/unittests/test_imperative_ocr_attention_model.py
index f3a231e7b28343eed6a546113ded20c20247d40f..3f53552ba48ccb761ec56d3bf8656a9d1d7dc79f 100644
--- a/python/paddle/fluid/tests/unittests/test_imperative_ocr_attention_model.py
+++ b/python/paddle/fluid/tests/unittests/test_imperative_ocr_attention_model.py
@@ -13,16 +13,11 @@
 # limitations under the License.
 from __future__ import print_function
 
-import contextlib
 import unittest
 import numpy as np
 import six
-import os
-from PIL import Image
-import paddle
 import paddle.fluid as fluid
 from paddle.fluid import core
-from paddle.fluid.optimizer import SGDOptimizer
 from paddle.fluid.dygraph.nn import Conv2D, Pool2D, FC, BatchNorm, Embedding, GRUUnit
 from paddle.fluid.dygraph.base import to_variable
 from test_imperative_base import new_program_scope
@@ -37,13 +32,13 @@ class Config(object):
     # size for word embedding
     word_vector_dim = 128
     # max length for label padding
-    max_length = 15
+    max_length = 5
     # optimizer setting
     LR = 1.0
     learning_rate_decay = None
 
     # batch size to train
-    batch_size = 32
+    batch_size = 16
     # class number to classify
     num_classes = 481
 
@@ -445,10 +440,7 @@ class TestDygraphOCRAttention(unittest.TestCase):
                 (i - 1) * Config.max_length,
                 i * Config.max_length,
                 dtype='int64').reshape([1, Config.max_length])))
-        #if Config.use_gpu:
-        #    place = fluid.CUDAPlace(0)
-        #else:
-        #    place = fluid.CPUPlace()
+
         with fluid.dygraph.guard():
             fluid.default_startup_program().random_seed = seed
             fluid.default_main_program().random_seed = seed
@@ -461,10 +453,7 @@ class TestDygraphOCRAttention(unittest.TestCase):
                     [50000], [Config.LR, Config.LR * 0.01])
             else:
                 learning_rate = Config.LR
-            #optimizer = fluid.optimizer.Adadelta(learning_rate=learning_rate,
-            #    epsilon=1.0e-6, rho=0.9)
             optimizer = fluid.optimizer.SGD(learning_rate=0.001)
-            # place = fluid.CPUPlace()
             dy_param_init_value = {}
             for param in ocr_attention.parameters():
                 dy_param_init_value[param.name] = param.numpy()