Abstract: In response to a series of problems restricting the production of the coal preparation plant,such as insufficient crushing capacity of the raw coal crusher, coal shutdown of the hand-selected belt, insufficient of the post, the high labor intensity and badly worn of the washing equipment, a technical reform of the large coal pre-discharge gangue process is researched and implemented.In the new process, using dense medium shallow slot sorter to sort big coals on 200-50 mm, using two dense medium and two-product cyclone to sort coals on 50.0-1.0 mm, using TSS slime separator to sort coals on 1.00-0.25 mm, using combined dewatering of pressure filter and plate frame filter press to sort fine coal slime on 0.25-0 mm.The results show that the new process of grading into lump and fine coal washing improves the production capacity of the coal preparation plant, improves the operating rate of the washing equipment, reduces the operating pressure of the slime water system, reduces the labor intensity of workers picking up gangue, ensures the product quality, improves separation efficiency, and creates considerable economic and social benefits.