Abstract: In order to reduce the disturbance effect of blasting action on adjacent filling body in the process of two-step mining and improve the stability and safety of filling body in the process of mining opera⁃ tion，the 90 m high section stope of Zhangzhuang Iron Mine is taken as the research object，and the research is carried out by combining LS-DYNA numerical simulation with field industrial test. A three-dimensional model containing explosives，ore bodies and filling bodies is constructed. The fluid-solid coupling algorithm is used to set the thickness of five kinds of wall protection mines of 2.0，2.3，2.5，2.8 and 3.0 m，and the in⁃ fluence range of blasting stress wave and the variation law of stress and displacement of filling bodies are an⁃ alyzed. Taking 406 stope as the object，the simulation results are verified by goaf scanning. The numerical simulation shows that with the increase of the thickness of the wall protection ore，the maximum influence range of the stress wave decreases from 2.74 m to 1.63 m，the peak value of the effective stress decreases from 2.125 MPa to 1.817 MPa，and the peak value of the effective displacement decreases from 0.414 mm to 0.149 mm. When the thickness is greater than 2.5 m，the filling body is only damaged by small damage. The industrial test shows that the filling body under the 2.0~2.5 m wall protection ore is obviously damaged，and there is basically no change at 3.0 m，which is consistent with the simulation results. It is clear that the opti⁃ mal thickness of wall protection ore in the 90 m high section in Zhangzhuang Iron Mine should not be less than 2.5 m，which provides a scientific basis for the optimization of mine blasting parameters and safe min⁃ ing.

Key words: blasting vibration, LS-DYNA, numerical simulation, filling body protection