diff --git a/paddle/fluid/operators/reader/CMakeLists.txt b/paddle/fluid/operators/reader/CMakeLists.txt
index c6df2646c4c83eea804e507c00ec2fc34a269e76..728197377df04df8c993a48bc282431473fe9959 100644
--- a/paddle/fluid/operators/reader/CMakeLists.txt
+++ b/paddle/fluid/operators/reader/CMakeLists.txt
@@ -16,7 +16,7 @@ function(reader_library TARGET_NAME)
 endfunction()
 
 cc_library(buffered_reader SRCS buffered_reader.cc DEPS reader simple_threadpool)
-reader_library(open_files_op SRCS open_files_op.cc)
+reader_library(open_files_op SRCS open_files_op.cc DEPS buffered_reader)
 reader_library(create_random_data_generator_op SRCS create_random_data_generator_op.cc)
 reader_library(create_shuffle_reader_op SRCS create_shuffle_reader_op.cc)
 reader_library(create_batch_reader_op SRCS create_batch_reader_op.cc)
diff --git a/paddle/fluid/operators/reader/open_files_op.cc b/paddle/fluid/operators/reader/open_files_op.cc
index daeacdb8b4d540e94d1c03bd33b0bbdb024f958d..74cda3ad980a72d68b2faf81f97aae95c72cebfb 100644
--- a/paddle/fluid/operators/reader/open_files_op.cc
+++ b/paddle/fluid/operators/reader/open_files_op.cc
@@ -18,6 +18,7 @@
 #include "ThreadPool.h"
 #include "paddle/fluid/framework/blocking_queue.h"
 #include "paddle/fluid/operators/reader/blocking_queue.h"
+#include "paddle/fluid/operators/reader/buffered_reader.h"
 #include "paddle/fluid/operators/reader/reader_op_registry.h"
 
 namespace paddle {
@@ -232,12 +233,17 @@ class OpenFilesOp : public framework::OperatorBase {
       container.reset(new OrderedReaderContainer());
     } else {
       container.reset(new PreemptiveReaderContainer(
-          std::min(file_names.size(),
-                   static_cast<size_t>(std::thread::hardware_concurrency()))));
+          static_cast<size_t>(Attr<int>("thread_num"))));
     }
 
-    out->Reset(
-        std::make_shared<MultiFileReader>(file_names, std::move(container)));
+    auto reader =
+        std::make_shared<MultiFileReader>(file_names, std::move(container));
+    auto buffer_size = Attr<int>("buffer_size");
+    if (buffer_size > 1) {
+      reader = framework::MakeDecoratedReader<BufferedReader>(
+          reader, platform::CPUPlace(), buffer_size);
+    }
+    out->Reset(reader);
   }
 };
 
@@ -253,6 +259,8 @@ class OpenFilesOpMaker : public FileReaderMakerBase {
       An OpenFilesOp creates a MultiFileReader, which is able to
       read data multi-threaded from multiple files.
     )DOC");
+    AddAttr<int>("thread_num", "Number of thread to read files.");
+    AddAttr<int>("buffer_size", "The reading buffer of these files.");
   }
 };
 
diff --git a/python/paddle/fluid/layers/io.py b/python/paddle/fluid/layers/io.py
index 9133038de237a0a9475c8667c5b9265c2d60e782..bfcf5ee7d87824e2c68da8ec935da8d77e7bab12 100644
--- a/python/paddle/fluid/layers/io.py
+++ b/python/paddle/fluid/layers/io.py
@@ -21,6 +21,7 @@ from ..layer_helper import LayerHelper
 from ..executor import global_scope
 from layer_function_generator import generate_layer_fn, templatedoc
 import sys
+import multiprocessing
 
 __all__ = [
     'data', 'BlockGuardServ', 'ListenAndServ', 'Send', 'Recv',
@@ -549,10 +550,9 @@ def open_files(filenames,
        shapes(list): List of tuples which declaring data shapes.
        lod_levels(list): List of ints which declaring data lod_level.
        dtypes(list): List of strs which declaring data type.
-       thread_num(None): Deprecated argument. It will be set by open_files
-            automatically.
-       buffer_size(None): Deprecated argument. It will be set by open_files
-            automatically.
+       thread_num(None): The number of thread to read files.
+            Default: min(len(filenames), cpu_number).
+       buffer_size(None): The buffer size of reader. Default: 3 * thread_num
        pass_num(int): Number of passes to run.
        is_test(bool|None): Whether `open_files` used for testing or not. If it
             is used for testing, the order of data generated is same as the file
@@ -574,14 +574,15 @@ def open_files(filenames,
          # Via the reader, we can use 'read_file' layer to get data:
          image, label = fluid.layers.io.read_file(reader)
     """
-    if thread_num is not None:
-        print >> sys.stderr, "thread_num parameter of open_files is " \
-                             "deprecated. It will be ignored and set " \
-                             "automatically by open_files "
-    if buffer_size is not None:
-        print >> sys.stderr, "buffer_size parameter of open_files is " \
-                             "deprecated. It will be ignored and set " \
-                             "automatically by open_files "
+    if thread_num is None:
+        thread_num = min(len(filenames), multiprocessing.cpu_count())
+    else:
+        thread_num = int(thread_num)
+
+    if buffer_size is None:
+        buffer_size = 3 * thread_num
+    else:
+        buffer_size = int(buffer_size)
 
     if isinstance(filenames, basestring):
         filenames = [filenames]
@@ -600,7 +601,9 @@ def open_files(filenames,
         'shape_concat': shape_concat,
         'lod_levels': lod_levels,
         'ranks': ranks,
-        'file_names': filenames
+        'file_names': filenames,
+        'thread_num': thread_num,
+        'buffer_size': buffer_size
     }
     if is_test is not None:
         attrs['is_test'] = is_test
diff --git a/python/paddle/fluid/tests/unittests/test_data_balance.py b/python/paddle/fluid/tests/unittests/test_data_balance.py
index 7fa4abc611621adcee1f2e32051efb19e53c4f04..aa09b0ea445adccae3f741b53850f8182f3270cc 100644
--- a/python/paddle/fluid/tests/unittests/test_data_balance.py
+++ b/python/paddle/fluid/tests/unittests/test_data_balance.py
@@ -155,7 +155,7 @@ class TestDataBalance(unittest.TestCase):
                 main_program=main_prog,
                 build_strategy=build_strategy)
 
-            if (parallel_exe.device_count > self.batch_size):
+            if parallel_exe.device_count > self.batch_size:
                 print("WARNING: Unittest TestDataBalance skipped. \
                     For the result is not correct when device count \
                     is larger than batch size.")