Simulated comminution that the coal impact rigid wall using finite element soft-ware of explicit formulation based on dynamics model of elastic collision (Hamilton varia-tionnal principle), the critical velocity of the coal impacting comminution was about 10 m/s, and validated the release effect of pressure in the coal impacting comminution, and then extend applied field of the finite element software of explicit formulation LS-DYNA analys-ing impact comminution of the elastic-plastic material. The simulation result has great guidance and reference value for understanding the impact comminution mechanics of coal and other material and manufacturing comminution equipment.