Abstract: The problems faced by Xiaohezui Mine′s Coal Preparation Plant are high content of gangue in raw coal, low yield of clean coal and high raw coal transportation and cleaning costs. In order to fix the problems, based on analysis of size and density composition of raw coal as well as the advantages and disadvantages of different gangue preremoval schemes, a study is made on the effects that can be obtained by using the pneumatic cleaning process. Study result shows with the use of the FX air separator as the primary separator for preremoval of waste from 80 ~ 13 mm raw coal at an actual separation density of 1.77 g/cm³, the ecart probable moyen is 0.165 g/cm³, the ash of the raw coal can be reduced from 66.28% to 44.73%, and a save of operating cost amounting to 4.175 million yuan can be expected per year. It indicates that waste preremoval can more feasibly be effected by using pneumatic separation method.