Abstract: In order to avoid the distortion of power spectral density of the artificial time history in seismic qualification test, the power spectral density envelope should be verified. On the basis of the relationship among floor response spectrum, Fourier amplitude spectrum and power spectral density, the method for generating target power spectral density is studied. Respectively using Kaul formula and SRP3.7.1 appendix A method, fast Fourier transform method are introduced to retrieve the power spectral density of floor spectrum and artificial acceleration. The basic assumptions and uncertainties of different methods and the differences of the shape and the peak value of the obtained power spectral density are comparatively analyzed. The method based on response acceleration and its fast Fourier transfer is recommended as the target power spectral density generating methodology.