Abstract: Gas explosion is serious accident that happens in coal mine from time to time, and study shows that obstacles can effect gas explosion. Numerical simulation was used to analyze the effect of different blockage ratios and different numbers of obstacles on gas explosion propagation. According to experiment result and experiment data, correct simulation model was selected in the paper. Different blockage ratios and different numbers of obstacles were simulated and the results were compared and analyzed. Gas explosion flame, pressure and temperature were monitored and analyzed, and flame development process was analyzed when it went through obstacle. The result shows that flame propagation velocity is increased because of obstacle, and blockage ratios and numbers of obstacles can affect flame propagation velocity greatly.