The motion forms(deformation) of the sliding soil along the slope include inviscid particle flow,viscous particle flow,and mass sliding.The motion forms were mainly influenced by the mechanical properties of the viscous mud medium filling.The effect of the medium filling on the motion forms of the sliding soil is worth discussing.The sliding soil can be seen as the mixture which is composed of the medium filling and coarse particles.The Chengdu clay with different moisture contents were selected as the medium filling.Their mechanical parameters were experimentally measured for simulating the moving process of the sliding soil.Different motion forms of the sliding soil were numerical simulated based on PFC3D by changing the specific mechanical parameters.The mechanical parameters of the Chengdu clay are experimentally determined.The numerical results show that with the moisture content of the filling slurry medium in the range of >302%,101%~182%,and <80%,the motion form of the sliding soil belongs to the inviscid particles flow(similar with the sliding sand),viscous particles flow(seen as the viscous flows);and masssliding(seen as the block sliding along the slope surface),respectively. The motion forms (deformation) of the sliding soil along the slope include inviscid particle flow, viscous particle flow, and mass sliding. The motion forms were mainly influenced by the mechanical properties of the viscous mud medium filling. The effect of the medium filling on the motion forms of the sliding soil is worth discussing.The sliding soil can be seen as the mixture which is composed of the medium filling and coarse particles.The Chengdu clay with different moisture contents were selected as the medium filling.Their mechanical parameters were experimentally measured for simulating the moving process of the sliding soil. Different motion forms of the sliding soil were numerical simulated based on on PFC3D by changing the specific mechanical parameters. mechanical parameters of the Chengdu clay are experimentally determined. numerical results show that with the moisture content of the filling slurry medium in the range of> 302%, 101% ~ 182%, and <80%, the motion form of the sliding s oil belongs to the inviscid particles flow (similar with the sliding sand), viscous particles flow (seen as the viscous flows); and masssliding (seen as the block sliding along the slope surface), respectively.