Basing on dry contact model of soft spheres the segregation processes of spherical and non-spherical particles were simulated using threes-dimensional discrete element methods（DEM）. Particle segregation mechanism was analyzed in view of force, torque and energy conversion between particles. Influence of segregation speed affected by particle size ratio was also discussed. The result shows that large particles are more active than small ones in segregation process, and non-spherical particles have higher energy, which makes up the influence of particle shape to segregation process to some extent, are more active than spherical particles. Average normal force, tangential force between large particles, their torque and kinetic energy are all greater than those of small particles. Particle segregation speed increases significantly with the increasing of size ratio. When the size ratio is greater than the critical value 3, the amplitude of increase in segregation speed will be slowed down.