The worst-hit area is Fujian province, where heavy rains have caused floods and landslides that have killed 26 people since May 29, Chinese state media said, citing Li Baojun, an official with the Ministry of Civil Affairs.
The official Xinhua News Agency, quoting provincial flood control authorities, said 212,000 people have been evacuated from the province.
Roads have been blocked by a series of landslides in Fuzhou, the capital of the province.
State television showed residents in Jian'ou, a city in Fujian, wading through murky waist-high flood water as they were evacuated from their homes.
In Guangdong province, 11 people were killed and another 60,000 to 70,000 were evacuated, the China Daily said.
Guizhou province and the city of Chongqing have also been hit by gales and hailstorms.
More rain is expected in central, eastern and southern provinces of China.