Abstract: According to the problem of difficult to treatment of coal slime water in Qianyingzi coal preparation plant,take different kinds of common coagulant and flocculant conducted the slurry settling test.The optimum reagent regime was obtain by study of the influence of the types and dosage of flocculant and coagulant,reagent adding order and composite reagent on coal slurry settling effect. At the last,we come to a conclusion through the technical and economic comparison that it can not only effectively reduce the concentration of washing water,but also can save reagent cost about 98. 4 ten- thousand yuan/year after the use of new reagent regime.