Abstract: 3D calculation model of Saturated soil foundation under impacting load was established by the FLAC 3D numerical software based on its non-linear character, fluid-solid coupling character and large deformation theory. The permeability coefficient ranging from 0.0001 cm/s to 0.1 cm/s was calculated in numerical simulation. The calculation results were applied to analyze the variation characteristics of displacement, pore pressure, density and plastic volume. The results show that the moment reinforcement effect of saturated soil is related to permeability during impacting. The permeability coefficient increases with the adding effect of instantaneous compaction.