Abstract: In order to improve classification efficiency of cyclone with screen mesh,based on design of cylinder screen mesh diameter and aperture diameter,inlet,overflow tube,cone angle and underflow outlet,model machine of cyclone with screen mesh is made; according to a change in underflow outlet diameter,its effect on classification of this cyclone is analyzed. The result shows that it is an increasing classification efficiency of this cyclone with increase of underflow outlet diameter,while particle size of classification decreases.