The quake was reported 8 miles east of Chabu and 110 miles south-southeast of Lanzhou in Gansu province. It was not immediately known if there were injuries or damage.
The China Earthquake Center measured the tremor at 6.6-magnitude at the junction of Minxian and Zhangxian counties, Xinhua News Agency reported.
The report quoted residents in Minxian county as saying the tremor, lasting about a minute, shook trees and homes. Lanzhou is the provincial capital.
Xinhua said the quake also was felt in Xi'an City, capital of neighboring Shaanxi province.