Abstract: In view of depletion of coal resources，the increase of ground subsidence caused by mining and geological disasters up in Guangxi Heshan Coal Seam，four shallow goafs in south-central part of Shangtang Mine are listed as research object to analyze the deformation and stress of roof and surface in mined-out area by building the three-dimensional numerical model with discrete element method，based on field investigation. The mechanism model of mining subsidence is discussed. The results show that: ①The goaf scale directly determines the degree of surface deformation，and the influence of surface soil's thickness is double acting;② Maximum of horizontal surface movement shift to downhill，and roof rock at downhill more easily results in breakage and caving;③ "two zones" have developed at the goaf overburden，and its main failure mode are tensile failure and shear failure;④The formation of shallow mining collapse is summarized as four stages: beginning，development，perforation and stable. Each stage has its typical characterization of deformation and stress.

Key words: Shallow seam, Mining collapse, Discrete Element Method, Failure mechanism