Abstract: Seismic slope dynamic response and the deformation mechanism are the premises of analyzing the dynamic stability of slopes. The response regulation of a bedding rock slope under the seismic action is discussed by using the three-dimensional finite difference software FLAC^3D. The deformation mechanism is analyzed through the plastic zone, displacement time-histories as well as changes of shear strain increment of key elements. The calculation shows that, under the seismic action, the amplification coefficients of the horizontal and vertical peak accelerations of the bedding rock slopes increase with the increasing elevation and come to the maximum at the structural plane and the top of the slope; those at the top of the slope increase with the decrease of the distance from the slope surface and come to the maximum at the structural plane; the rock mass has vertical amplification effect on the input seismic waves and its filtering effect is inferior to the soil slope; the deformation damage of rock slopes mainly comes from the weak structural plane, formed by upper tension failure and bottom shear failure; the research also gives the methods of determining the position of the sliding surface of bedding rock slope^’s and the judgment of slope instability. The results of the research have certain significance to analyzing the stability of bedding rock slopes and seismic design.