The coal sample is coal slime from Wangjiazai. In order to solve the problem of slime flotation in a wide size range, high ash slime entrainment caused serious, flotation concentrate ash, coal is low, seriously affect the quality problems in coal flotation. Through particle size analysis, determination of the particle size of contact angle, the slime classification granularity is 0.074mm. 0.5mm~ 0.074mm and less than 0.074mm two particle size flotation, through the two step release test, analysis of its flotation and flotation effect. Grading flotation to improve the yield of flotation clean coal, reducing the ash content of flotation concentrate, improve the adverse effects of high ash slime on the flotation.