Abstract: This paper presents an impulsive wave formula calculating system. It is based on geohazard impulsive wave formula and local head loss theory. . It takes into account on varied impulsive effect generated by varied landslides, decaying difference on varied region, frictional head loss and local head loss. It adopts many topography parameters. So its result is strongly objective. This paper takes impulsive wave generated by Gongjiafang for example and analyzes the impulsive wave. The results are close to the results of field investigation. The biggest impulsive wave height is 33.15 m. It is concluded that in the rapidly decaying area, the impulse wave has an average decrease of 4 m in wave amplitude within the distance of 100 m. While in the mildly decaying area, that figure is change to 0.11 m. Also it is found that there is an amplified decaying effect when the wave propagates from gorge to strath.