The main objective of this study was to investigate the effect of input earthquake characteristics on the seismic response of a homogenous step-like rock slope. A sequence of shaking table tests was performed in a large-scale physical model with a size of 3.50 m, 0.68 m and 1.20 m in length, width and height, respectively. Results showed that the absolute peak ground acceleration motion amplification factor in horizontal direction (AAF-X) of upper part of the slope was amplified comparison with that at the slope toe while the absolute peak ground acceleration motion amplification factor (AAF-Z) acquired maximum value at the lower position of the slope. With the increasing of the excitation frequencies, the AAF-X around the slope crest increased firstly and then deceased, while the AAF-Z increased continuously. Seismic response of the slope showed strongest amplification when the normalized height of the slope H/λ (ratio of slope height to wavelength) was around 0.2 and AAF-X exhibited a decrease trend when H/λ was larger than 0.2. The AAF showed nonlinear tendency with the increases of the input amplitudes, especially near the shoulder of the slope. This phenomenon can be revealed by the relationship between the calculated resonance frequency or damping ratio of the slope and the amplitude of the input motion. The excitation amplitude has a “double-effect” on the seismic response of a step-like homogeneous rock slope. That is on the one hand, the larger the excitation amplitude, the stronger the acceleration intensity, the greater deterioration of rock slope structure or material and the larger damping ratio of the slope; on the other hand, more energy will be dissipated due to plastic deformation or particle friction of high damping ratio and weaker slope structure. These results could attribute to reveal the dynamic instability mechanism of the homogeneous slope.