diff --git a/easyquotation/helpers.py b/easyquotation/helpers.py
index 11ba7cc..d9184e9 100644
--- a/easyquotation/helpers.py
+++ b/easyquotation/helpers.py
@@ -2,6 +2,7 @@
 import json
 import os
 import re
+
 import requests
 
 STOCK_CODE_PATH = os.path.join(os.path.dirname(__file__), "stock_codes.conf")
@@ -27,15 +28,18 @@ def get_stock_codes(realtime=False):
 def get_stock_type(stock_code):
     """判断股票ID对应的证券市场
     匹配规则
-    ['50', '51', '60', '90', '110'] 为 sh
-    ['00', '13', '18', '15', '16', '18', '20', '30', '39', '115'] 为 sz
-    ['5', '6', '9'] 开头的为 sh， 其余为 sz
-    :param stock_code:股票ID, 若以 'sz', 'sh' 开头直接返回对应类型，否则使用内置规则判断
-    :return 'sh' or 'sz'"""
-    assert type(stock_code) is str, "stock code need str type"
-    sh_head = ("50", "51", "60", "90", "110", "113", "118",
-               "132", "204", "5", "6", "9", "7")
-    if stock_code.startswith(("sh", "sz", "zz")):
+    ['4'， '8'] 为 bj
+    ['5', '6', '7', '9', '110', '113', '118', '132', '204'] 为 sh
+    其余为 sz
+    :param stock_code:股票ID, 若以 'sz', 'sh', 'bj' 开头直接返回对应类型，否则使用内置规则判断
+    :return 'bj', 'sh' or 'sz'"""
+    assert isinstance(stock_code, str), "stock code need str type"
+    bj_head = ("4", "8")
+    sh_head = ("5", "6", "7", "9", "110", "113", "118", "132", "204")
+    if stock_code.startswith(("sh", "sz", "zz", "bj")):
         return stock_code[:2]
-    else:
-        return "sh" if stock_code.startswith(sh_head) else "sz"
+    elif stock_code.startswith(bj_head):
+        return "bj"
+    elif stock_code.startswith(sh_head):
+        return "sh"
+    return "sz"