Distinct element method (DEM) is based on Newton's second law of motion and the basic law of particles between elements colliding. It's an effective numerical method which widely used in many engineering fields by using dynamic relaxation method on Iterative calculation. By comparing the linear contact model and nonlinear contact model of DEM, Cundall spring-damp-sliding contact model had been selected as our major studying model. Then the coordinate of the contact point, “composite quantity” of each contact unit and the relative velocity between units in this system had been calculated. And finally the numerical simulation on the motion state of single granule and granule group had be done.