In view of the infection of part extraction of stope floor pillar on the integral stability of stope in Puqing Iron Mine,the floor pillar extraction was simulated with 3D FEM,the results of rock mass rating(RMR) classification were compared and analyzed.The results of numerical simulation showed that if the floor pillar is mined partially,the stress in pillars will sharply increase,so integral stability of mine may weaken.Based on the distribution patterns of stress field after floor pillar extraction,some suggestions were presented for the future mining of the ore remained in stope.