Abstract: Integrated technology of fully mechanized backfill mining and raw coal separation in underground coal mine is used to solve the problems of too high content of gangue in raw coal and repeated transportation of waste rock packing and subsidence during the process of mining thin seam. The paper systematically stated the system layout of the raw coal separation and backfill mining integrated technology, the operational mechanism of coal and gangue separation system, backfill and coal mining system were analyzed respectively, the key factors restricting the effect of backfilling and its control measures were got as well. The results of application show that after coal and gangue separated from raw coal are transported to coal bunker and goaf respectively, which brings huge economic, social and environmental benefits by reducing the ash content of raw coal from 70% to 25%, avoiding the repeated transportation of gangue, optimizing the backfilling system, controlling the surface subsidence effectively, selecting about 30 000 tons coal from waste rocks and saving transportation costs about 4.05 million in one workplace every year.