diff --git a/paddle/fluid/operators/detail/grpc_server_test.cc b/paddle/fluid/operators/detail/grpc_server_test.cc
index cb2b8dd538176461652ff4fcd96bfdb906eedb14..b8db0ad987cdfaec1fc9236c3f26e88891376dce 100644
--- a/paddle/fluid/operators/detail/grpc_server_test.cc
+++ b/paddle/fluid/operators/detail/grpc_server_test.cc
@@ -108,10 +108,7 @@ void StartServer(const std::string& endpoint) {
   rpc_service_->RunSyncUpdate();
 }
 
-// NOTE(yuyang18) : This test is buggy.
-// 1. We should not use port 8889 before check.
-// 2. We should not use sleep(2) to sync threads.
-TEST(PREFETCH, DISABLED_CPU) {
+TEST(PREFETCH, CPU) {
   // start up a server instance backend
   std::thread server_thread(StartServer, "127.0.0.1:8889");
   sleep(2);
diff --git a/paddle/fluid/operators/send_recv_op_test.cc b/paddle/fluid/operators/send_recv_op_test.cc
index 2bb46cecb484fa2b413ccd577be6bf6edee42f99..d5303eaf50722234d205264e56892b1723104d53 100644
--- a/paddle/fluid/operators/send_recv_op_test.cc
+++ b/paddle/fluid/operators/send_recv_op_test.cc
@@ -151,7 +151,7 @@ void StartServerNet(bool is_sparse, std::atomic<bool> *initialized) {
   LOG(INFO) << "server exit";
 }
 
-TEST(SendRecvOp, DISABLED_CPUDense) {
+TEST(SendRecvOp, CPUDense) {
   std::atomic<bool> initialized{false};
   std::thread server_thread(StartServerNet, false, &initialized);
   while (!initialized) {
@@ -197,7 +197,7 @@ TEST(SendRecvOp, DISABLED_CPUDense) {
   paddle::operators::ListenAndServOp::ResetPort();
 }
 
-TEST(SendRecvOp, DISABLED_CPUSparse) {
+TEST(SendRecvOp, CPUSparse) {
   std::atomic<bool> initialized;
   initialized = false;
   std::thread server_thread(StartServerNet, true, &initialized);
diff --git a/paddle/fluid/operators/test_send_nccl_id.cc b/paddle/fluid/operators/test_send_nccl_id.cc
index 719f039a0f5fcd7445bf1589a683f122e6d62ba0..bbae1d54aa3524fd45cb8ab13c86df8d54b8e643 100644
--- a/paddle/fluid/operators/test_send_nccl_id.cc
+++ b/paddle/fluid/operators/test_send_nccl_id.cc
@@ -63,7 +63,7 @@ void StartServer(std::atomic<bool>* initialized) {
   server_thread.join();
 }
 
-TEST(SendNcclId, DISABLED_Normal) {
+TEST(SendNcclId, Normal) {
   std::atomic<bool> initialized{false};
   std::thread server_thread(StartServer, &initialized);
   while (!initialized) {
diff --git a/python/paddle/fluid/tests/unittests/CMakeLists.txt b/python/paddle/fluid/tests/unittests/CMakeLists.txt
index 70b7bee04fa6ca6688d8746fcf833155784abbea..0e274f769962a2b43959ff49cfba65094396672f 100644
--- a/python/paddle/fluid/tests/unittests/CMakeLists.txt
+++ b/python/paddle/fluid/tests/unittests/CMakeLists.txt
@@ -41,8 +41,10 @@ function(py_test_modules TARGET_NAME)
 endfunction()
 list(REMOVE_ITEM TEST_OPS test_warpctc_op)
 list(REMOVE_ITEM TEST_OPS test_dist_train)
+list(REMOVE_ITEM TEST_OPS test_parallel_executor_crf)
 foreach(TEST_OP ${TEST_OPS})
     py_test_modules(${TEST_OP} MODULES ${TEST_OP})
 endforeach(TEST_OP)
 py_test_modules(test_warpctc_op MODULES test_warpctc_op ENVS FLAGS_warpctc_dir=${WARPCTC_LIB_DIR} SERIAL)
 py_test_modules(test_dist_train MODULES test_dist_train SERIAL)
+py_test_modules(test_parallel_executor_crf MODULES test_parallel_executor_crf SERIAL)
diff --git a/python/paddle/fluid/tests/unittests/test_parallel_executor_crf.py b/python/paddle/fluid/tests/unittests/test_parallel_executor_crf.py
index fc79bf3b275ccabc9622b2ef3ab64e289651d8f9..66e138b03f3b170aca4fb2207438eb9af1783c33 100644
--- a/python/paddle/fluid/tests/unittests/test_parallel_executor_crf.py
+++ b/python/paddle/fluid/tests/unittests/test_parallel_executor_crf.py
@@ -168,28 +168,24 @@ class TestCRFModel(unittest.TestCase):
                           pe.run(feed=feeder.feed(cur_batch),
                                  fetch_list=[avg_cost.name]))[0]
 
-    @unittest.skip("Hang when parallel execute")
     def test_update_sparse_parameter_all_reduce(self):
         build_strategy = fluid.BuildStrategy()
         build_strategy.reduce_strategy = fluid.BuildStrategy.ReduceStrategy.AllReduce
         self.check_network_convergence(
             is_sparse=True, build_strategy=build_strategy)
 
-    @unittest.skip("Hang when parallel execute")
     def test_update_dense_parameter_all_reduce(self):
         build_strategy = fluid.BuildStrategy()
         build_strategy.reduce_strategy = fluid.BuildStrategy.ReduceStrategy.AllReduce
         self.check_network_convergence(
             is_sparse=False, build_strategy=build_strategy)
 
-    @unittest.skip("Hang when parallel execute")
     def test_update_sparse_parameter_reduce(self):
         build_strategy = fluid.BuildStrategy()
         build_strategy.reduce_strategy = fluid.BuildStrategy.ReduceStrategy.Reduce
         self.check_network_convergence(
             is_sparse=True, build_strategy=build_strategy)
 
-    @unittest.skip("Hang wen parallel execute")
     def test_update_dense_parameter_reduce(self):
         build_strategy = fluid.BuildStrategy()
         build_strategy.reduce_strategy = fluid.BuildStrategy.ReduceStrategy.Reduce
diff --git a/python/paddle/fluid/tests/unittests/test_warpctc_op.py b/python/paddle/fluid/tests/unittests/test_warpctc_op.py
index 65afbd3876e5710e27cdc4f04b3483cf0dce043d..ac638f7836f8205f80e31cfd5eb8892b2c7aee08 100644
--- a/python/paddle/fluid/tests/unittests/test_warpctc_op.py
+++ b/python/paddle/fluid/tests/unittests/test_warpctc_op.py
@@ -210,11 +210,9 @@ class TestWarpCTCOp(OpTest):
         self.outputs = {"Loss": loss}
         self.attrs = {"blank": self.blank, "norm_by_times": self.norm_by_times}
 
-    @unittest.skip("This unittest could be hang")
     def test_check_output(self):
         self.check_output()
 
-    @unittest.skip("This unittest could be hang")
     def test_check_grad(self):
         self.outputs['WarpCTCGrad'] = self.gradient
         self.check_grad(["Logits"], "Loss", max_relative_error=0.007)