Abstract: Take the long wall mining of shallow-buried coal seam under thin base rock in Yangjiacun western mining area as the engineering background, using two dimension discrete element numerical analysis software UDEC, the mining process of working face was simulated, the laws that roof movement has suddenness and coherence and surface subsidence exhibits a jagged subsidence fault zone on the surface were summarized and analyzed. The laws are basically consistent with the actual situation. On this basis, the mine adopted a series of technical measures to effectively avoid secondary disasters and losses.