Is there a direct train from guangzhou south train station to foshan?

No. All direct trains depart from Main Railway Staion. The train schedules 05:19, 05:30, 06:00, 07:30, 10:25, 11:36, 12:35, 13:50, 15:15, 15:47, 17:20, 17:32, 18:00, 19:08, 19:18, 19:42, 21:46 and 22:09. It takes around half an hour.

Or you can take direct long-distance bus at South Bus Station. The bus schedules are from 08:40 to 21:30 with the interval of 15 to 20 mins. From the South Railway Station, just walk east around 820 yards to arrive at the bus station.