This paper is based on dynamic shear modulus formula and correlative parameters of loess gained from three triaxial tests. The tests were acted by random seismic load. A subprogram of MSC. Marc was programmed. Finite element model acted by artificial earthquake wave was built to study dynamic response of loess slope. So, the displacement, velocity and stress transformation law of loess slope were analyzed when excellent frequency, amplitude and action direction of input seismic wave was changed. The results show that excellent frequency of slope displacement, velocity response time-history is much smaller than the input wave. A large number of high frequency wave was filtered when seismic wave transmit in slope soil. And dynamic response of loess slope was affected by the predominant frequency of seismic wave strongly. A giving slope was exceptional sensitive to certain seismic wave with predominant frequency.