Abstract: In this paper, the non-stationary stochastic seismic motion model presented by authors is used to analyze stochastic seismic response of a supergiant pile group foundation employed to support the bridge. The pile group-soil-pier structure is treated as a whole and the finite element method and complex response technique are used to perform the analysis. Firstly, the input time-frequency evolutionary power spectrum is defined according to the intensity and energy information of target acceleration time-history. Secondly, stochastic seismic responses of a free field and a pile group-soil-pier structure system under a nonstationary stochastic seismic excitation are analyzed respectively, and the dynamic pile group-soil-pier structure interaction is discussed. Finally, the effects of frequency nonstationarity on seismic responses of the interaction system are discussed.