Te van carrying 15 kindergarten children and one teacher plunged into a roadside pond this morning at Guixi City in Jiangxi Province, a spokesman for the local government said.
Three children died on the spot while another eight died at a local hospital, state-run Xinhua news agency reported.
The four injured are in stable condition, the spokesman said, adding the pond is about three to four meters deep.
Police have detained the van's driver for questioning.
Overcrowding on Chinese school buses is common in rural areas. Today's accident is the latest in a string of deadly crashes in China involving school children.
Last year, a small school van overloaded with 62 children crashed head-on with a truck in western China, leaving 19 people dead.