Abstract: In order to recover the limited coking coal resource, improve utilization efficiency of coking coal, the pater takes the heavy-medium preparation middlings from Xi qu coal preparation as the study object, did the experiment on the crushing、the very fine grinding、step by step releasing and floccules-flotation inhibitor’s optimization. The result shows that taking the experiment on step by step releasing is difficult to obtain the high-yield and low-ash clean coal for the Xi qu heavy-medium preparation middlings; But through the experiment on the floccules-flotation, the paper obtained the high-yield and low-ash clean coal whose yield is36.31% and ash is 17.64. In order to reduce the ash of clean coal, the experiment on the floccules-floation inhibitor’s optimization about its kind and dosage is taken and obtain the clean coal whose ash is 12.83%.It offers a new way to the quality –improving technology of high-quality coking coal.