Abstract: In order to prevent and reduce the damages caused by mine gas explosions, the self made horizontal pipeline type flammable gas-dust explosion device was applied to simulate the mine roadway.Under the normal atmospheric temperature and constant pressure, there were four different shape obstacles applied to study the variation laws of the gas explosion pressure and flame spreading velocity.The results showed that the obstacle existed would have obvious influences to the gas ex plosion, would increase the explosion pressure and flame spreading velocity and would change the variation law of the explosion pressure. The obstacle shape could ha ve the different degree influence to the gas explosion. The dam board obstacle could make the highest explosion pressure and flame spreading velocity.The four bore ri ng would have a min influence.