Abstract: Based on the condition of cracking ore and rock body and low strength in Houhemushan mining area of Gushan iron mine,the paper put forward the depressurization sublevel caving method instead of the openstope method to mine the medium-thickness ore;To simulate the problem,a numerical analysis method,FLAC_3D is applied to analysis the depressurization range of sublevel caving method.The paper determined the suitable stope structure by the numerical results,so formed the depressurized mining scheme of sublevel caving method to mine medium-thickness and sloping ore body and implementing now.