hello, several bus stations of Guangzhou have scheduled lines to Xiamen everyday. Among them, the Tianhe Interstate Bus Terminal supplies the most frequently buses. The fare is 220yuan per head.
Timetable: 7:20, 8:10, 9:00, 9:50, 10:40, 11:40, 13:00, 15:00, 18:20, 19:00, 20:00, 20:20, 20:40, 21:00, 21:20, 21:40, 22:00, 22:20, 22:50
The station could be reached easily. There are lots of public buses could take you there and it is also the terminal of Guangzhou subway Line3.