Gas explosion is very disastrous accident all over the world. Influence scope analysis of shock wave and smoke after gas explosion is of great importance and significance. The results indicate that, during the process of shock wave propagation destroying the air throttle, the shock wave energy will be consumed as part of air throttle destruction, which causes the overpressure reduced. However, the shock wave continues to be propagated and attenuated to a certain distance. Results on analyzing influence scope of smoke flow show that the smoke temperature and concentration in roadway are higher before restoring ventilation. The smoke is diluted by the fresh air through diffusion. After restoring ventilation, the temperature and concentration of smoke flow are lowered greatly. In conclusion, the influence scope study of shock and smoke flow is of full practice.