Hi, I'm going to Guangzhou via Singapore airline and then change to China Southern airline to Sanya. I only have 2 hours in between, is it too short?

Yeah, time is a little tight.

As I know, there are two areas in the airport, Area A and Area B. You will arrive at Area B by international arrival, but you'd better make it clear which area you will leave first. If it is in the same area, hurry up and you may be able to catch the flight. If it is in different areas, I'm afraid you may miss it.