diff --git a/paddle/fluid/framework/parallel_executor.cc b/paddle/fluid/framework/parallel_executor.cc
index 74945fb4f2f745b6ca9c48adb0c8b9e6ae1e94a4..1bb089c344cea326902a2010d6e916a4c85acd28 100644
--- a/paddle/fluid/framework/parallel_executor.cc
+++ b/paddle/fluid/framework/parallel_executor.cc
@@ -115,14 +115,12 @@ void ParallelExecutor::BCastParamsToGPUs(
 
   for (auto &var : vars) {
     auto *main_var = main_scope->FindVar(var);
-    if (!main_var->IsType<LoDTensor>()) {
+    if (main_var == nullptr || !main_var->IsType<LoDTensor>()) {
       continue;
     }
 
     auto &main_tensor = main_var->Get<LoDTensor>();
-
     auto &dims = main_tensor.dims();
-
     if (paddle::platform::is_gpu_place(main_tensor.place())) {
       size_t numel = main_tensor.numel();
       ncclDataType_t data_type = platform::ToNCCLDataType(main_tensor.type());
diff --git a/paddle/fluid/operators/read_op.cc b/paddle/fluid/operators/read_op.cc
index 2925b8a85da1b0d19672124e49c8fd22c8b4e6bf..4496110cf80d5e954f0dbab3e45d56a98a51f155 100644
--- a/paddle/fluid/operators/read_op.cc
+++ b/paddle/fluid/operators/read_op.cc
@@ -66,13 +66,6 @@ class ReadOp : public framework::OperatorBase {
     std::vector<std::string> out_arg_names = Outputs("Out");
     std::vector<framework::LoDTensor> ins;
     reader->ReadNext(&ins);
-    if (ins.empty()) {
-      reader->ReInit();
-      reader->ReadNext(&ins);
-      PADDLE_ENFORCE(
-          !ins.empty(),
-          "Reader can not read the next data even it has been re-initialized.");
-    }
     PADDLE_ENFORCE_EQ(ins.size(), out_arg_names.size());
     for (size_t i = 0; i < ins.size(); ++i) {
       auto* out =
diff --git a/paddle/fluid/operators/reader/create_threaded_reader_op.cc b/paddle/fluid/operators/reader/create_threaded_reader_op.cc
index 854381e0eee163cd9193452da34f34f7797e191d..7b10135afcb3b5424a0e20032b427fb1b0284e4c 100644
--- a/paddle/fluid/operators/reader/create_threaded_reader_op.cc
+++ b/paddle/fluid/operators/reader/create_threaded_reader_op.cc
@@ -111,7 +111,7 @@ class CreateThreadedReaderOpMaker : public DecoratedReaderMakerBase {
                   "When 'unsafe_mode' is false, invoking 'HasNext()' or "
                   "'ReInit()' is not allowed to avoid unexpected bugs in "
                   "multi-thread environment.")
-        .SetDefault(false);
+        .SetDefault(true);
     AddComment(R"DOC(
       CreateThreadedReader Operator
 
@@ -134,6 +134,6 @@ class CreateThreadedReaderOpMaker : public DecoratedReaderMakerBase {
 }  // namespace paddle
 
 namespace reader = paddle::operators::reader;
-REGISTER_FILE_READER_OPERATOR(create_threaded_reader,
-                              reader::CreateThreadedReaderOp,
-                              reader::CreateThreadedReaderOpMaker);
+REGISTER_DECORATED_READER_OPERATOR(create_threaded_reader,
+                                   reader::CreateThreadedReaderOp,
+                                   reader::CreateThreadedReaderOpMaker);
diff --git a/python/paddle/fluid/layers/io.py b/python/paddle/fluid/layers/io.py
index 4901521db5bceed78c0b146dc1134eff69d04461..d016ab90081a5c6a6b567cb67b371eb8dce1c002 100644
--- a/python/paddle/fluid/layers/io.py
+++ b/python/paddle/fluid/layers/io.py
@@ -350,7 +350,7 @@ def open_recordio_file(filename,
         main_prog_var = multi_pass(reader=main_prog_var, pass_num=pass_num)
 
     if for_parallel:
-        main_prog_var = for_parallel(reader=main_prog_var)
+        main_prog_var = parallelize(reader=main_prog_var)
 
     return monkey_patch_reader_methods(main_prog_var)
 
@@ -435,12 +435,12 @@ def open_files(filenames,
             reader=main_prog_reader, pass_num=pass_num)
 
     if for_parallel:
-        main_prog_reader = for_parallel(reader=main_prog_reader)
+        main_prog_reader = parallelize(reader=main_prog_reader)
 
     return monkey_patch_reader_methods(main_prog_reader)
 
 
-def __create_unshared_decorated_reader__(op_type, reader, attrs={}):
+def __create_shared_decorated_reader__(op_type, reader, attrs):
     var_name = unique_name(op_type)
     startup_blk = default_startup_program().current_block()
     startup_var = startup_blk.create_var(name=var_name)
@@ -456,7 +456,7 @@ def __create_unshared_decorated_reader__(op_type, reader, attrs={}):
     return monkey_patch_reader_methods(main_prog_var)
 
 
-def __create_shared_decorated_reader__(op_type, reader, attrs={}):
+def __create_unshared_decorated_reader__(op_type, reader, attrs):
     new_reader_name = unique_name(op_type)
     main_blk = default_main_program().current_block()
     new_reader = main_blk.create_var(name=new_reader_name)
@@ -488,8 +488,9 @@ def multi_pass(reader, pass_num):
         'create_multi_pass_reader', reader, {'pass_num': int(pass_num)})
 
 
-def for_parallel(reader):
-    return __create_shared_decorated_reader__('create_threaded_reader', reader)
+def parallelize(reader):
+    return __create_shared_decorated_reader__('create_threaded_reader', reader,
+                                              {})
 
 
 def read_file(file_obj):