Guangzhou international airport to shantou

Well, you may take metro line 3 from CAN to Jiahewanggang Station, and change to metro line 2 to South Railway Station. Then, take a high speed train to Chaoshan (about 3 hours). Upon arrival, take a bus to ST.

The distance is about 280 miles (450km), and it costs about CNY 1500 to 2000 per taxi. By the way, one taxi can hold four passengers at most. :)

Why cant we take direct train to ST. And please tell me the cost..if i take the train

Firstly, no direct train runs from the airport nowadays.
In addition, there are only two schedules from Guangzhou to ST. One is at 08:35 from East Railway Station. The duration is 7.5 hours. The other one is at 13:12 from Main Railway Station. It takes around 8 hours.
So Chaoshan Train Station +Coach are recommended.
Actually, Chaoshan railway station is in the middle of Chaozhou, ST, and Meizhou and serves passengers to these three cities. It is only about 15 miles from ST downtown.