Abstract: This paper presents a numerical study on the dynamic effect on the mechanics behavior of subgrade near the high-rise residential community. Three-dimensional finite difference analysis based on Mohr-Coulomb criterion is adopted. The mechanics characteristics and failure mode under static and seismic conditions were discussed by FLAC^3D. The numerical results showed that subgrade is safe under static and seismic conditions. Under the seismic, both horizontal acceleration and vertical acceleration have amplification effect along the elevation, especially the horizontal acceleration is amplified largely. The amplification effect at slope surface and slop body is different which indicates the air front effect. As the elevation increasing, the frequency component of the slope around its natural vibration frequency is significant amplified and other high frequency components were filtered. Ground motions of different amplitudes(PGA=0.15, 0.45, 0.62g) have different effect on dynamic response of acceleration. The subgrade slope under the horizontal seismic wave has amplification effect to input seismic waves, and the effect become extremely prominent around the crest of the slope. The subgrade slope under the vertical seismic wave behaves differently, the amplification effect enhances evidently near the crest of the inner slope. Geogrid reinforcement can greatly improve the seismic stability of the embankment.