From Guangzhou Airport to Hong Kong

There not direct bus service from Guangzhou Baiyun International  airport to Hong Kong You just need to by Guangzhou Metro at the Guangzhou Airport , Line 3 (Guangzhou Airport to Guangzhou East Railway Station),Then you can by direct train from Guangzhou east railway staton to Hung Hom, Hong Kong . The last express train is 21:32 to Hung Hum.

Or you can by train from Guangzhou East Railway station to the Shenzhen Luohu, The last train is 23:02,one hour to Shenzhen , you can by metro at Luohu to Hong Kong.

You can read more from here: Train from Guangzhou to Hong Kong  Guangzhou Metro Map