The explosion took place this morning at the small coal mine belongsing to Linli Coal Mining Co Ltd in Shizuishan City in the Ningxia Hui Autonomous Region.
Twenty miners were working underground at the time of the accident, state-run Xinhua news agency reported.
One mine worker died after he was rescued from the shaft and the bodies of 17 miners have been pulled above the ground.
More than 200 rescuers have been mobilised.
Most of the miners were from the provinces of Sichuan and Gansu, as well as Ningxia autonomous region.
Mining accidents are common in China, which is the world's largest coal producer. Ninteen people were killed in March in a similar accident in the northern Shanxi province.