The movement track of the solid particles in a cyclone separator has been studied by numerical simulation. Discrete phase model (DPM) was adopted for solid field. The physical mechanism for the particles movement in a cyclone separator is studied by analyzing the influence of different particle size and inlet velocity on solid particles track in a cyclone separator. The results show that the particles track in a cyclone separator is complex, and it is influenced by inlet velocity and particles size simultaneously. The track of same size particles is different at the case of different inlet velocity, and small particles are easier influenced by the inlet velocity. The simulation results could provide some theoretical guide for engineering applications.