In order to study the transportation efficiency of the aggregate device of coal cleaning machine, taking a certain type of coal cleaning machine as the research object, establishing the mechanical model of interaction between particles and blades, obtaining the relationship between force and speed.Based on the Archard wear theory and discrete element method, Coupling model of screw and coal was established by EDEM.Analyzing the transportation capacity of screw by controlling variable, the influence of coal particle size and rotating speed on the wear depth of screw was studied.The results show that increasing the rotating speed can improve the coal transportation efficiency in terms of speed control, but too fast speed will cause particles to fly out along the radial direction.The wear depth of the screw decreases first and then increases with speed changing in from 20 r/min to 65 r/min.When speed is increased from 35 r/min to 50 r/min, the efficiency improvement effect is the most significant.,the torque of screw is relatively small at the same time.In conclusion, the best range of screw speed is 35 r/min～ 50 r/min.In addition, the screw wear is serious when transporting large coal particles compared with small particles.Therefore, in practical application, the transportation of large coal should be carried out at low screw speed.Based on the above conclusion, in this paper, an optimal mathematical model is established to minimize the driving torque, obtaining the optimal structure and dynamic parameters of the screw, and proving the correctness of optimization process by simulation test.It provides a theoretical reference for improving the transportation efficiency of the coal cleaning machine, reducing the energy consumption of the equipment and prolonging the service life of the equipment.