Abstract: In order to analyze the gas explosion mechanism in low gassy mine, the paper stated the necessary condition and the explosion cause of the gas explosi on in the low gassy mine.Taking one low gas explosion accident occurred in No.1 Mine of Lu'an Xinjiang Company as an example, the paper explained and studied the process and cause of the gas explosion.The results showed that due to the coal spontaneous combustion make the fire source around the explosion point, high temper ature carbonizations would occur in the seam around the fire point.During the high temperature carbonization process, great combusted and explosive gas would be rel eased and the fresh air in the sealed fired zone would be rapidly reduced.With the detection, the oxygen volume fraction in the mixed gas was over 12% and the gas vol ume fraction in the air return flow was 2.13% with a distance of 300 m to the fired point.According to the calculation, the gas content at the fired point would more highe r.Due to meet the three factor conditions of the gas explosion (gas, fire, oxygen)，a gas explosion accident would occure.