The particle flow analysis method is introduced and applied to simulate a rock slope. The joints are formed according to the practical data; and the mechanical parameters of joints are smaller than those of the rock. When the retaining wall below fails to function completely; the movement process of the landslide is calculated and forecasted; and the deformation of the whole landslide

displacements and stresses of various positions

are analyzed. The upside powder clay slips resulting from ripping within itself

while downside gravel slip because of the destruction of the retaining wall and decrease of the tensile stress. The 2 sliding planes are determined and the suggestions for treatment are proposed.