I would like to know the timetable for the bus, from Hong Kong to Yangshuo? The overnight one thx!

I'm afraid there is no direct bus between. I suggest you take East Rail Line to Lo Wu, HK and cross the immigration border to Shenzhen Luohu. Then at Shenzhen Railway Station bus stop to take bus no. 352 or 7 or take a taxi to Yinhu Bus Station, where there are buses to YS.