Abstract: The stability of open-pit mine waste dump is significantly affected by blasting dynamic load in mining. In order to study the influence of inner dump stacking on the dynamic stability of adjacent open-pit slope under blasting vibration，taking Jianshan Phosphate Mine as the engineering background， FLAC3D numerical simulation method was used，the response characteristics of acceleration，displacement and shear strain of the slope before and after the stacking of the inner dump under the action of blasting seismic wave are compared and analyzed. The results show that the internal dump dump can significantly reduce the dynamic response of the slope，and the peak acceleration（PGA）amplification factor at the top of the slope is reduced by 25%（from 2.0 to 1.5），the peak displacement of the slope is significantly re⁃ duced from 50.87 mm to 4.764 mm，the peak shear strain increment is reduced from 0.009 9 to 0.000 8， and the anti-deformation ability is significantly enhanced，from the circular slip surface before stacking to the discontinuous and localized shear zone after stacking. It is concluded that the stacking of the inner dump can effectively improve the dynamic stability of the slope by changing the geometric shape and wave impedance distribution of the slope，absorbing and dissipating seismic wave energy，provide backpressure support，and provide a scientific basis for the safety design of mine dump and the slope treatment under the influence of blasting.

Key words: waste dump, blasting seismic wave, dynamic response characteristics, numerical simula? tion