Abstract: Abstract: in the process of separating coarse slime, the bottom flow of the cyclone group is fine and the effect of degrading of the arc screen is poor. After the analysis and study of the Tianhong coal preparation Co., Ltd., the large diameter cyclone and the laminated vibrating screen are used together for the fine classification and ash reduction of coarse slime, and the classification process model of coarse slime is innovated, and the coarse coal is effectively reduced in the coarse coal. The content of high ash and fine mud has been popularized and applied in the coal preparation plant of Pingma Shenma Group, and the effect is remarkable.