Abstract: For two-dimensional slope stability analysis method, such issues as the end effect of slope, the lateral bending of sliding surface, the plane bending of slope, and the lateral heterogeneity are often ignored. Due to the soft inter-layers generated by the abandoned soft rocks or the sliding slope along the ground, the slopes of the dump are irregular with obvious end effects. To this end, the two-dimensional simplified Bishop method is extended to be three-dimensional to make a stability analysis for the dump. Since this method ignores the effect of the vertical shear between different blocks, it does not require the assumptions made in two-dimensional method during the extending process, with the feature of simple calculation and effective in wide range. The calculations show that the safety factor obtained by three-dimensional stability analysis is higher than that by two-dimensional calculation, and is more practical.