Slope interlayered by sand rock, mud rock and macker in Qianfuyan Formation in the Middle Jurassic generated deformation, such as cracks, relaxation, and creeping along soft discontinuities. According to detailed study of rock mass structure, soft interlayer was confirmed as key discontinuity for slope stability, and then the stability of superficial slope in cataclastic texture rock mass and blocks combined by discontinuities were analyzed, which indicated that superficial slope stability was worse, and the stability of large scale block was better. The result accorded with the deformation of slope.