The whales were up to 65 feet long and ranged in weight from 22 to 44 tons, Xinhua News Agency reported.
A city government spokesman said the whales were found alive about 6 a.m. Friday but efforts to refloat them failed and they died.
Xu Xinrong, a senior animal researcher at Nanjing Normal University, said it was the first mass beaching of whales in China, since six whales died in southeastern China's Fujian province in 1985.
He said whale beachings are a natural phenomenon, the cause of which is not clearly understood.
Kate Middleton recycles dress at movie premiere
Benedict Cumberbatch's dramatic reading of R. Kelly lyrics is just what you need