May i know how to go Great Wall from Wang Fu Jing by subway & bus?

Gigi, could you specify which section you are going to visit? There are several sections that are worth your visit. If you never visit the wall before, I personally think you should visit Badaling section first. If you are interested in the wall, then you can visit other sections next time.

You can take subway line 1 from Wangfujing, get off at Fuxingmen. There you can take subway line 2 and get off at Jishuitan. Then you can walk from there to Deshengmen. There you can take no.877 or 919 bus to the wall.