Abstract: The shallow ore rock in Zhongjiu Iron Mine is weak and broken，and the traditional sub⁃ level open stoping with subsequent filling mining method faces a serious risk of collapse.In order to im ⁃ prove the safety and efficiency of mining，aiming at the downward drift filling mining method，FLAC3D fi⁃ nite element numerical simulation is used to analyze the dynamic changes of stress and displacement of ar ⁃ tificial false roof and pillar under different drift width (4 .0 ~5.0 m)and height (3 .8 ~5.0 m).The safety factor (ratio of ultimate tensile strength to maximum tensile stress)is used to evaluate the stability of stope.The re⁃ sults show that the maximum displacement and maximum tensile stress of the stope increase with the in ⁃ crease of the width and height of the approach.The safety factor of the original rock pillar is 0.86 ~1.25， and the safety factor of the artificial false roof is 1.37 ~1.86.The safety factor of each scheme is greater than 1.0 in the two-step mining.Considering the safety and mining efficiency，the recommended stope structure parameters are 4.5 m wide and 4 m high (Scheme 5).The safety factor of artificial roof under this scheme is 1.53，which meets the stability requirements.The research results provide a scientific basis for the optimi ⁃ zation of stope structure parameters in Zhongjiu Iron Mine.

Key words: downward drift filling mining method, stope structure parameters, FLAC3D, factor of safe? ty, stability analysis