Official Chinese news agency Xinhua reported that 30 people were working in the mine at the time of the explosion, which occurred around 6:50pm.
Four people trapped in the mine were confirmed dead by rescuers, while one of the 26 workers who escaped the mine died in hospital. One miner received non-fatal injuries in the blast.
The mine, owned by Wanlong Mining, was fully registered, with annual output of 150,000 tons.
Following the accident all coal mines in Yuxian were ordered to suspend operations.