Abstract: This paper develops a model about stress waves propagation in rock slope body according to the theory of stress waves propagation.Based on the theories of elasticity,it derives the elastic-dynamics equations and potential functions.Taking SH wave propagation as an example,the stress waves superposition at different parts of the slope is discussed.The sloping surface and slope crest are departed into two independent free surfaces.They do not affect each other in the process of reflecting stress waves.The stress waves superposition beside the two free surfaces are analyzed respectively.The amplitude of the superposed wave is discussed.It reveals the rules of both vertical and horizontal dynamic response amplifications of the slope.The rule for the vertical dynamic response amplification is that getting closer to slope surface,the particles' oscillation amplitude increase.The rule for the horizontal dynamic response amplification is that near slope crest,the particles' oscillation response increases,and reaches to the largest at slope crest.The condition for the two rules being cyclic variation is that the slope height is larger than 1/4 wavelength of SH wave.