Abstract: A landslide occurred near the discharge water tower of Jinpen reservoir in Xian.It was a residual body of the downstream boundary segment of old landslide 1~# on the right bank of the Jinpen reservoir.A shortterm strong precipitation induced deformation of the slope and its sliding motion.The landslide was drawn with bedding-plane slip.At different plane sections,extents of the deformation and breakdown were different.The motion is similar to the plane rotation of a slope.The landslide was controlled by four group structure planes.The softening schistosity surface has the dipping direction from 150 to 170 and the dip angle from 35 to 55.The second structure interface has the dipping direction from 230 to 290 and dip angle from 35 to 55.They formed the control surfaces of sliding motion.The causes of the landslide are the softening schistosity surface,the strong precipitation,the gentle inclined and defective ground cover,and the gunite covering layer at the bottom of the slope.