Abstract: In order to find out appropriate reagents for coal slurry processing in Xintian coal preparation plant,according to coal slurry assay,taking poly aluminium chloride,magnesium chloride as coagulant,polyacrylamide as flocculent,the effect of different combination of reagents on coal slurry settling is investigated,with analysis of economic benefit of coal preparation plant after optimized categories and dosage of reagents. The application shows that flocculent play crylamide adding appropriate magnesium chloride can improve coal slurry settling,which not only saves water and dosage of regents,but optimize products and increases economy benefit.