Abstract: To solve the problems of poor settling effect of coal slurry,high slime content of qualified medium and the unstable of separation system and product index in Xingcun coal preparation plant,optimized and reformed the original process equipment and regime of agent. By taken measures of strengthen fine slime recovering,alternate using thickener,reducing washed quantity of raw coal and optimizing flotation reagent system,the concentration of circulating water maintained below 3 g/L,the slime content of qualified medium reduced and separation system reaches stability,eventually,the process system operated normally.