Abstract: A numerical analysis model of slope dynamic response was established with FLAC program to study slope response rules at different dynamical loads and different rock parameters. The results show that the dynamic response magnification coefficient of a slope under dynamical load is not proportional to the dynamical load frequency. There exists a dominant frequency at which the dynamic response magnification coefficient is larger than those at other frequencies. According to the simulation results, the dominant frequency is dependent on the shear modulus and density of the rock mass. A functional relation of the dynamical response magnification coefficient with dynamical load and rock mechanics parameters was put forward.