In this paper, a number of artificial earthquake ground motions compatible with time-frequency characteristics of recorded actual earthquake ground motion as well as the given target response spectrum are generated using wavelet transform. The variation of maximum displacement, velocity and acceleration responses of SDOF elasto-plastic systems by excited these artificial earthquake ground motions are evaluated numerically and theoretically. The coefficients of variation of maximum displacement, velocity and acceleration responses are shown in the case of the ground motion using the time-frequency characteristics of recently actual occurred large earthquake motions. Under the given design response spectrum, a selection manner of generated artificial earthquake ground motion which causes larger maximum displacement response of elasto-plastic structure are suggested.