Abstract: According to the problem of gas explosion characteristics in mine closed fire zone, FLACS software is used to establish a simple closed space to simulate pressure changes, temperature changes and flame development during gas explosion. The results show that the reflection of pressure wave causes the gas explosion pressure curve to fluctuate repeatedly, and multiple pressure peaks appear; the temperature fluctuates less in the vicinity of the fuel zone, and the fluctuation range is larger in the slightly distant position. While at a distance closer to the end, the temperature value is very small compared to the previous monitoring point; the flame has a reverse propagation phenomenon, followed by turbulence until the end of the reaction.