Abstract: Abstract:In order to study the stability of mined -out area, FLAC -3D numerical simulation of the stress distribution law and surrounding rock deformation is carried out on the basic of detailed investigation and mechanical test. The researches show that : empty area between the column and the normal stress of roof and floor show the normal stress clusters with the orebody stoping of each stage；offset increases accordingly with the increase of stope stress；pillar shear failure may form under the action of compressive stress.