diff --git a/python/paddle/fluid/io.py b/python/paddle/fluid/io.py
index b4764bdd7de07a83b7345b41f4563b5c0f50e0c4..c92eebcdab73cb83ad0ba96baa3aed454a4ba40c 100644
--- a/python/paddle/fluid/io.py
+++ b/python/paddle/fluid/io.py
@@ -197,11 +197,15 @@ def _get_valid_program(main_program):
     elif isinstance(main_program, CompiledProgram):
         main_program = main_program._program
         if main_program is None:
-            raise TypeError("program should be as Program type or None")
+            raise TypeError(
+                "The type of input main_program is invalid, expected tyep is Program, but received None"
+            )
         warnings.warn(
             "The input is a CompiledProgram, this is not recommended.")
     if not isinstance(main_program, Program):
-        raise TypeError("program should be as Program type or None")
+        raise TypeError(
+            "The type of input main_program is invalid, expected type is fluid.Program, but received %s"
+            % type(main_program))
     return main_program
 
 
@@ -705,7 +709,9 @@ def load_vars(executor,
         if main_program is None:
             main_program = default_main_program()
         if not isinstance(main_program, Program):
-            raise TypeError("program's type should be Program")
+            raise TypeError(
+                "The type of input main_program is invalid, expected type is fluid.Program, but received %s"
+                % type(main_program))
 
         load_vars(
             executor,
@@ -721,7 +727,9 @@ def load_vars(executor,
             main_program = default_main_program()
 
         if not isinstance(main_program, Program):
-            raise TypeError("program should be as Program type or None")
+            raise TypeError(
+                "The type of input main_program is invalid, expected type is fluid.Program, but received %s"
+                % type(main_program))
 
         # save origin param shape
         orig_para_shape = {}
@@ -769,7 +777,7 @@ def load_vars(executor,
             orig_shape = orig_para_shape.get(each_var.name)
             if new_shape != orig_shape:
                 raise RuntimeError(
-                    "Shape not matching: the Program requires a parameter with a shape of ({}), "
+                    "Variable's shape does not match, the Program requires a parameter with the shape of ({}), "
                     "while the loaded parameter (namely [ {} ]) has a shape of  ({}).".
                     format(orig_shape, each_var.name, new_shape))
 
@@ -1385,7 +1393,7 @@ def get_parameter_value(para, executor):
             p = fluid.io.get_parameter_value(param, exe)
 
     """
-    assert is_parameter(para)
+    assert is_parameter(para), "The input variable is not parameter."
 
     get_program = Program()
     block = get_program.global_block()
@@ -1531,7 +1539,7 @@ def save(program, model_path):
 
     base_name = os.path.basename(model_path)
     assert base_name != "", \
-        "model_path MUST be format of dirname/filename [dirname\\filename in Window], Now filename is empty str"
+        "The input model_path MUST be format of dirname/filename [dirname\\filename in Windows system], but received model_path is empty string."
 
     dir_name = os.path.dirname(model_path)
     if dir_name and not os.path.exists(dir_name):
@@ -1642,7 +1650,7 @@ def load(program, model_path, executor=None, var_list=None):
                 raise e
             except:
                 raise RuntimeError(
-                    "Failed to load model file , please make sure model file is saved with the "
+                    "Failed to load model file, please make sure model file is saved with the "
                     "following APIs: save_params, save_persistables, save_vars")
 
             return
@@ -1658,7 +1666,7 @@ def load(program, model_path, executor=None, var_list=None):
             for var in var_list:
                 if var.name not in program_var_name_set:
                     raise LookupError(
-                        "loaded var [{}] not included in program variable list")
+                        "loaded var [{}] is not in program variable list")
 
             dir_name, file_name = os.path.split(model_path)
             try:
@@ -1903,11 +1911,11 @@ def set_program_state(program, state_dict):
             orig_para_np = np.array(var_temp.get_tensor())
             new_para_np = state_dict[para.name]
             assert orig_para_np.shape == new_para_np.shape, \
-                "Shape not matching: the Program requires a parameter with a shape of ({}), " \
+                "Parameter's shape does not match, the Program requires a parameter with the shape of ({}), " \
                 "while the loaded parameter (namely [ {} ]) has a shape of  ({})." \
                     .format(orig_para_np.shape, para.name, new_para_np.shape)
             assert orig_para_np.dtype == new_para_np.dtype, \
-                "Dtype not matching: the Program requires a parameter with a dtype of ({}), " \
+                "Parameter's data type does not match, the Program requires a parameter with a dtype of ({}), " \
                 "while the loaded parameter (namely [ {} ]) has a dtype of  ({})." \
                     .format(orig_para_np.dtype, para.name, new_para_np.dtype)
 
diff --git a/python/paddle/fluid/tests/unittests/test_io_save_load.py b/python/paddle/fluid/tests/unittests/test_io_save_load.py
new file mode 100644
index 0000000000000000000000000000000000000000..01665597facb225329f14fe76796a252ca14dd77
--- /dev/null
+++ b/python/paddle/fluid/tests/unittests/test_io_save_load.py
@@ -0,0 +1,52 @@
+#   Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import print_function
+
+import unittest
+import paddle.fluid as fluid
+from paddle.fluid import core
+
+
+class TestSaveLoadAPIError(unittest.TestCase):
+    def test_get_valid_program_error(self):
+        # case 1: CompiledProgram no program
+        graph = core.Graph(core.ProgramDesc())
+        compiled_program = fluid.CompiledProgram(graph)
+        with self.assertRaises(TypeError):
+            fluid.io._get_valid_program(compiled_program)
+
+        # case 2: main_program type error
+        with self.assertRaises(TypeError):
+            fluid.io._get_valid_program("program")
+
+    def test_load_vars_error(self):
+        place = fluid.CPUPlace()
+        exe = fluid.Executor(place)
+        # case 1: main_program type error when vars None
+        with self.assertRaises(TypeError):
+            fluid.io.load_vars(
+                executor=exe, dirname="./fake_dir", main_program="program")
+
+        # case 2: main_program type error when vars not None
+        with self.assertRaises(TypeError):
+            fluid.io.load_vars(
+                executor=exe,
+                dirname="./fake_dir",
+                main_program="program",
+                vars="vars")
+
+
+if __name__ == '__main__':
+    unittest.main()