diff --git a/download_speed/config.py b/download_speed/config.py
index 5433f3b..313bd4a 100644
--- a/download_speed/config.py
+++ b/download_speed/config.py
@@ -1,6 +1,8 @@
 import argparse
 import json
 import sys
+import os
+import inspect
 
 print("Config is loaded.")
 _g_args = None
@@ -23,8 +25,13 @@ def read_json():
     global _g_args
     json_path = _g_args.config
     if json_path is None:
-        print("specify json path")
-        sys.exit()
+        default_config_file_path = find_config_file_path()
+        if not os.path.exists(default_config_file_path):
+            print("specify json path")
+            sys.exit()
+        else:
+            json_path = default_config_file_path
+    print("load config from {file_path}".format(file_path=json_path))
     with open(json_path, "r", encoding="utf-8") as json_f:
         js = json.load(json_f)
         return js
@@ -57,6 +64,16 @@ def get(_setting):
         return None
 
 
+def find_config_file_path():
+    current_frame_file_path = os.path.dirname(
+        os.path.realpath(inspect.getfile(inspect.currentframe()))
+    )
+    config_file_dir = os.path.dirname(current_frame_file_path)
+    config_file_path = config_file_dir + "/config.json"
+    config_file_path = config_file_path.replace("\\", r"/")
+    return config_file_path
+
+
 init_config()
 setting = _json_obj