首先用命令pip install itchat安裝itchat，然後進到你要獲取的群裡去選擇“儲存到通訊錄”那裡將選項滑到右邊選上，沒有儲存到通訊錄的群是取不到資訊的。
以下程式碼在Win7和Python3.7裡除錯通過。

__author__ = 'Yue Qingxuan'
# -*- coding: utf-8 -*-
import itchat
import time
import datetime
from itchat.content import TEXT
roomslist = []
itchat.auto_login(hotReload=True)


def getroom_message(n):
    #獲取群的username，對群成員進行分析需要用到
    itchat.dump_login_status() # 顯示所有的群聊資訊，預設是返回儲存到通訊錄中的群聊
    RoomList =  itchat.search_chatrooms(name=n)
    if RoomList is None:
        pass
        #print("{0} group is not found!".format(name))
    else:
       # print('取得：',RoomList[0]['UserName'])
        return RoomList[0]['UserName']

def getchatrooms():
    #獲取群聊列表
    roomslist = itchat.get_chatrooms()
    #print('列表',roomslist)
    return roomslist


print("程式開始：",datetime.datetime.now())
for i in getchatrooms():
    roomslist.append(i['NickName'])

with open('群使用者名稱.txt', 'w', encoding='utf-8')as f:
    f.write("你一共加入了{0}群".format(str(len(roomslist))))
    for n in roomslist:
        ChatRoom = itchat.update_chatroom(getroom_message(n), detailedMember=True)
        f.write('\n\n------------------------------群名稱：'+ChatRoom['NickName']+"該微信群一共有{0}個成員".format(str(len(ChatRoom['MemberList'])))+'----------------------------------\n')
        #print("ChatRoom",ChatRoom)
        for i in ChatRoom['MemberList']:
            f.write('省份：'+i['Province']+" NickName為："+i['NickName']+" RemarkName為："+i['RemarkName']+'\n')
    f.close()
    print("程式結束：",datetime.datetime.now())