A series of minor aftershocks followed the first quake that hit the Yiliang county in Yunnan province and Weining county in the neighboring Guizhou province at 11:19 am (03:19 GMT).
All the victims are from Zhaotong district in Yiliang county and more than 100,000 people had been evacuated in Yunnan province by 3 pm, local media reported quoting an official with the province's civil affairs department.
Reports showed that more than 20,000 houses were damaged in the quakes.
According to the Chinese provincial seismological bureau, 16 aftershocks, the strongest measuring 5.6 on the Richter scale, were recorded till 1 pm local time. The epicenter of the quakes was in Yiliang county.
Hundreds of people rushed to the streets from offices and houses in the affected areas, the BBC reported. No casualty was reported from the Guizhou province. However, many houses were damaged in the area.