Abstract: With the continuous development of the expansion of the city, located in the peri-urban settlement of the coal mining basin of the city's security and development pose a serious threat and obstacle to treatment for the coal mined-out area collapse, to resume the land use functions, need to look at the ground floor deposit Caused by mining and surface rock cover damage to the law. UDEC through numerical simulation software, using discrete element method to study the steep thick seam mining damage to surrounding law, the law of surface deformation, deformation and failure analysis of its main characteristics and migration laws. Steep come thick seam mining damage to the main coal seam at the top of the development, the existence of an effective roof limited the damage to the roof of the development side of the floor of the destruction of small, dark surface groove surface subsidence pits, put forward in the process of exploitation Or the use of sub-standard top-down mining method can be filled in a timely and effective control of the surrounding rock breaking the affected area, on top of the old side can build permanent buildings and green belts, the use of the land to restore functionality.