The mass evacuation has taken place since Wednesday in and around the city of Dazhou in the southwestern province of Sichuan, China Central Television reported on Saturday.
Highways leading to Dazhou – about 450km from the provincial capital of Chengdu – have been cut off, and water levels in streets have risen to the height of three-storey buildings, state media said.
Over the past three days, Dazhou has been hit by 461mm of rainfall, the highest in a century. State media did not give estimates of economic losses.
Floods across China have killed more than 560 people and displaced 2.5 million this year, causing direct economic losses of about $2.77bn, government officials said.
The country is ravaged by floods and simultaneous droughts every summer, causing enormous loss of life.
Deforestation compounds the problem, as torrential rain triggers rock slides and mud flows off denuded mountainsides.