According to news agency Xinhua, China's National Energy Administration revealed that the 266 lives were lost from gas accidents in 47 coal mines.
While the death toll continues to fall each year, the NEA says there are still too many accidents.
China reportedly extracted 17 billion cubic metres of coalbed gas in 2014, up 9.2% from 2013, while 18.5bcm was targeted for 2015.
Flooding accidents also claim many lives in Chinese coal mines every year.