Abstract:The sublevel ore house method in an iron ore mine in Yunnan province is taken as the research background, occurrence conditions of ore body by field engineering geological survey and indoor rock mechanics experiment, CAD, numerical simulation software ANSYS and FLAC3D are used to study the different mining heights of sublevel chamber method.piecewise according to each step 10 m height of excavation, the stope stress, displacement and plastic zone under different segment the change of the three parameters were analyzed, and the results show that the When the sublevel height reach 40 m, stope roof tensile failure happened in the process of excavation area, between the columns are well versed in the shear failure of the plastic zone, 30 m sublevel stope is in stable condition, mining excavation under different sublevel height form has not been the minimum principal stress is beyond tensile strength of rock mass and footwall on stope roof and floor and the vertical displacement of lateral displacement are in stope safety, within the scope of the comprehensive analysis to select the best sublevel height of 30 m, is of great significance for mine safety production instruction, It provides reference for similar mines.