Abstract: In order to study the influence of obstacle on the gas explosion pressure, the horizontal ducted testing system for gas explosion was used. Experimental r esearch of gas explosion pressure was carried out in the horizontal explosion tube with obstacles.Influence rule of shape, blocking ratio and distance between obstacle was researched.The results show that the maximum pressure for gas explosion appeared at the strip-type obstacle.The secondary was the bow-type obstacle and ring-t ype obstacle has the least effect on gas explosion pressure.The gas explosion pressure increased with the addition of blocking-ratio and increased slowly with the spaci ng of obstacles.Compared with the shape and blocking-ratio of obstacle, the obstacle spacing has the least influence on the gas explosion pressure.The gas explosion pressure first decreased and then increased with the addition of tube slenderness ratio under different obstacles and the maximum increasing located in the slendernes s ratio of 64.