Based on a description of the calculation of slip velocity, we analyze the advantages and weaknesses of the algorithms proposed by Pan Jiazheng and Wang Yang , and put forward a more reasonable method which adds water resistance and water pressure difference method to the above methods. The concept of fluid resistance to the actual project named E’gongdai ancient landslide is applied. Based on five different optimization methods of the above two methods, and combining with E′gongdai ancient landslide, we calculate the acceleration and velocity of landslide. Considering the effect of cohesion, water pressure difference of both sides of slice and water resistance on the on the sliding velocity, we know that the effect of the above three factors on the sliding velocity decreases.