About 30 people were injured while watching tidal movements at Qiantang River in Haining, Zhejiang province, on Thursday, according to Hangzhou-based Qianjiang Evening News.
Although there is still one month to go for the best tidal spectacle, usually around mid-September, a typhoon and spring tide contributed to a 7-meter-high tide.
The tide destroyed a 100-meter-long wire net and a 30-meter-long wall at the river, the country's most famous location for tide-watching.
Eleven people were kept in hospital.
The local government has decided to close tidal-viewing areas for three days.