diff --git a/python/paddle/fluid/incubate/fleet/base/role_maker.py b/python/paddle/fluid/incubate/fleet/base/role_maker.py
index b9cd73d158497eac08a1b3988783b60f0cdfb8f2..9f3c7a8fd33d28dd7baccb0a50fb5f714c9ffb76 100644
--- a/python/paddle/fluid/incubate/fleet/base/role_maker.py
+++ b/python/paddle/fluid/incubate/fleet/base/role_maker.py
@@ -14,9 +14,10 @@
 """Defination of Role Makers."""
 
 from __future__ import print_function
-from multiprocessing import Process, Manager
+import multiprocessing
 import paddle.fluid as fluid
 import os
+import sys
 import time
 
 __all__ = [
@@ -602,7 +603,7 @@ class GeneralRoleMaker(RoleMakerBase):
         if ip_port != "":
             self._http_ip_port = ip_port.split(":")
             # it's for communication between processes
-            self._manager = Manager()
+            self._manager = multiprocessing.Manager()
             # global dict to store status
             self._http_server_d = self._manager.dict()
             # set running status of http server
@@ -636,9 +637,15 @@ class GeneralRoleMaker(RoleMakerBase):
                         "all": len(worker_endpoints) + len(eplist)
                     }
                     # child process for http server
-                    self._http_server = Process(
-                        target=self.__start_kv_server,
-                        args=(self._http_server_d, size_d))
+                    if sys.version_info >= (3, 8) and sys.platform == 'darwin':
+                        self._http_server = multiprocessing.get_context(
+                            'fork').Process(
+                                target=self.__start_kv_server,
+                                args=(self._http_server_d, size_d))
+                    else:
+                        self._http_server = multiprocessing.Process(
+                            target=self.__start_kv_server,
+                            args=(self._http_server_d, size_d))
                     self._http_server.daemon = True
                     # set running status to True
                     self._http_server_d["running"] = True
diff --git a/python/paddle/fluid/tests/unittests/test_device_guard.py b/python/paddle/fluid/tests/unittests/test_device_guard.py
index 7b05f6b0f24b3dcb5984db1c05ec22c442b07d64..681501d8d9d0b59e8d33c5774efc9a22b4f03170 100644
--- a/python/paddle/fluid/tests/unittests/test_device_guard.py
+++ b/python/paddle/fluid/tests/unittests/test_device_guard.py
@@ -33,6 +33,14 @@ def execute(main_program, startup_program):
     exe.run(main_program)
 
 
+def get_vaild_warning_num(warning, w):
+    num = 0
+    for i in range(len(w)):
+        if warning in str(w[i].message):
+            num += 1
+    return num
+
+
 class TestDeviceGuard(unittest.TestCase):
     def test_device_guard(self):
         main_program = fluid.Program()
@@ -108,7 +116,10 @@ class TestDeviceGuard(unittest.TestCase):
                         i = fluid.layers.increment(x=i, value=1, in_place=True)
                         fluid.layers.less_than(x=i, y=loop_len, cond=cond)
 
-        assert len(w) == 1
+        warning = "The Op(while) is not support to set device."
+        warning_num = get_vaild_warning_num(warning, w)
+        assert warning_num == 1
+
         all_ops = main_program.global_block().ops
         device_attr_name = core.op_proto_and_checker_maker.kOpDeviceAttrName()
         for op in all_ops:
@@ -138,7 +149,10 @@ class TestDeviceGuard(unittest.TestCase):
                         shape=[1], value=4.0, dtype='float32')
                     result = fluid.layers.less_than(x=x, y=y, force_cpu=False)
 
-        assert len(w) == 2
+        warning = "\'device_guard\' has higher priority when they are used at the same time."
+        warning_num = get_vaild_warning_num(warning, w)
+        assert warning_num == 2
+
         all_ops = main_program.global_block().ops
         device_attr_name = core.op_proto_and_checker_maker.kOpDeviceAttrName()
         for op in all_ops:
diff --git a/python/paddle/fluid/tests/unittests/test_framework_debug_str.py b/python/paddle/fluid/tests/unittests/test_framework_debug_str.py
index 72f43e56ccbe04f56cfd5a655fb57c58369039bb..6511b56b5e8236f6c336e29ac54bc626fd271c61 100644
--- a/python/paddle/fluid/tests/unittests/test_framework_debug_str.py
+++ b/python/paddle/fluid/tests/unittests/test_framework_debug_str.py
@@ -22,7 +22,7 @@ class TestDebugStringFramework(unittest.TestCase):
     def test_debug_str(self):
         p = Program()
         p.current_block().create_var(name='t', shape=[0, 1])
-        self.assertRaises(ValueError, callableObj=p.__str__)
+        self.assertRaises(ValueError, p.to_string, True)
 
 
 if __name__ == '__main__':
diff --git a/python/paddle/fluid/tests/unittests/test_save_model_without_var.py b/python/paddle/fluid/tests/unittests/test_save_model_without_var.py
index b74a6e10917f71b669a2d2e6906d6c7310c59c7e..4c63dced83b199acaffc3e703785b3eb8ec8913b 100644
--- a/python/paddle/fluid/tests/unittests/test_save_model_without_var.py
+++ b/python/paddle/fluid/tests/unittests/test_save_model_without_var.py
@@ -50,7 +50,7 @@ class TestSaveModelWithoutVar(unittest.TestCase):
                 params_filename='params')
             expected_warn = "no variable in your model, please ensure there are any variables in your model to save"
             self.assertTrue(len(w) > 0)
-            self.assertTrue(expected_warn == str(w[0].message))
+            self.assertTrue(expected_warn == str(w[-1].message))
 
 
 if __name__ == '__main__':