Abstract: There are tow separation systems A and B existed in Xingtai coal preparation plant,that one system is vibration bend screen+slime centrifuge and other is hydro-sizing cyclone + vibration bend screen + slime centrifuge.Based on the test,the paper analyzed and compared the separation result of two processes.The test result shows that under the same property of feed,for the ash reduction of coarse slime,the system A is batter than system B.