The stochastic seismic response characteristics of base isolation sliding system subjected to seismic motion is usually expressed in mean square response. Mean square response is used to evaluate absorbed energy. In this study, this system which was evaluated by root mean square (RMS) response was obtained by excitation experiment using nonstationary random vibration. In addition, this system was modeled by single degree of freedom system with sliding mechanism, and this system of stationary random vibration response was evaluated by analysis. Furthermore, the relationship of friction coefficients with RMS response of this system was calculated by analysis. As results, increasing magnitude of input, mean square responses increases. And, decreasing the friction coefficient on this system, RMS response of relative displacement increases in case of the power spectral density with 0.1[cm^2/s^3]. On the other hand, RMS response of absolute acceleration decreases when the friction coefficient was less than 0.14[-]. When the friction coefficient was greater than 0.14[-], it increases. Increasing the power spectral density, RMS responses increase.