It was an organised, premeditated terrorist attack, Xinhua reported citing the authorities.
The incident occurred in the capital city of Yunnan province when a group of terrorists attacked people with knives at the Kunming railway station at around 9 p.m., causing death and injuries, police said.
The Kunming station, located in the downtown area of the city, is one of the largest railway stations in China.
Chinese President Xi Jinping urged the law enforcement to solve the case with all efforts and punish the terrorists in accordance with the law.
Yang Haifei, a resident of Yunnan province who was attacked and sustained injuries on his chest and back said, he was buying a ticket when a group of people rushed into the station, most of them in black dress, and started attacking people.
"I saw a person come straight at me with a long knife and I ran away with everyone," he said, adding that people who were slower were severely injured.
Train departures, however, have not been affected, the Kunming railway bureau said.
The security management bureau under the ministry of public security called the incident a "severe violent crime".