Abstract: High speed soil-cutting simulation system based on Smooth Particle Hydrodynamics(SPH) methods and Finite Element Methods(FEM) was developed. Applying this system high speed soil-cutting process can be simulated to discover soil-tool interacting mechanism. This paper also arose a simulation instance of back-rotary tilling. By high-speed camera the woking process of back-rotary tilling was recorded. Compared high-speed photo with simulation end, the basic conclusion is that the simulation system can be applied to high-speed soil cutting simulation. This simulation system will help to improve innovation design level of high-speed cultivation machine such as high-speed plow and high-speed rotary tiller.