Abstract: The paper introduced the separation mechanism of the selective flocculation.The CPAM300 selected as the selective flocculant was applied to the floatat ion experiment and the selective flocculation separation experiment on the slime with high ash and fine coal.The results showed that with the selective flocculant adde d,the clean coal production rate and the combustible mass recovery rate could be highly improved,the clean coal production rate could be highly improved 25%,the max recovery rate of the combustible mass could be improved 26. 50% and the max floatation perfect index could be improved 9.78%. When the usage of selective flocculant increased,the floatation perfect index would be firstly increased and then decreased.The optimized value would be 1020 g/t.The adding sequence of the collector-floccul ant-foaming agent would be better than the sequence of the flocculant-collector-foaming agent.