The quake, with a focal depth of just five kilometres, was felt strongly in Jinggu Dai and Yi Autonomous County in Yunnan province on Tuesday.
The casualties were reported mainly from Jinggu County, the epicentre of the quake.
A total of 92,700 people in Jinggu have been affected out of which 56,880 are relocated, an official with the county’s publicity department told state-run Xinhua news agency on Wednesday.
The quake shook the county at 9:49 pm (local time) with a focal depth of five kilometres.
Tremor was felt across the province, which is prone to earthquake disasters.
Yunnan has initiated the Class-I emergency response, the highest, sending rescue staff and materials to the affected areas.
On August 3, a 6.5-magnitude quake hit Ludian, Yunnan, killing more than 600 people.
Back in 1970, a strong 7.7-magnitude quake in Yunnan had killed at least 15,000 people.