The “gas accident” at Nantong Mining Company’s Yanshitai coal mine occurred at 5.40pm on Tuesday evening (local time).
Six of the 28 miners working in the shaft at the time were able to escape, with two taken to hospital with injuries.
Rescuers have recovered the bodies of the 22 deceased miners.
Coal mining accounts for less than 4% of the Chinese workforce but is responsible for about 45% of industrial fatalities, making it the largest occupational hazard in the country.
China’s coal mines have been labelled the deadliest in the world due to lax enforcement and the unrelenting need to feed China’s insatiable need for coal.
The latest accident follows the deaths of 20 miners in April when a coal mine in China's southwest Yunnan province flooded, leaving miners trapped.
In 2013, China recorded 589 mining-related accidents, leaving 1049 people dead or missing, according to the Chinese government.
However, both the number of accidents and fatalities were down more than 24% from 2012.