Abstract: To reduce the loss of coarse clean coal effectively,solve the problem of poor dewatering effect caused by only filtering flotation concentrate in Gongwusu coal preparation plant,CSS-3. 0 type coarse coal slime separator is used to separating coarse coal slime and the mixture of coarse clean coal and flotation concentrate is dewatered by press filter and then structure,working principle,technical characteristics,technical parameters of the separator are introduced and analyzed. The application shows that yield of coarse clean coal is increased by 0. 3% and ash of products meets requirement.