Abstract: Artificial time histories are key data inputs for the calculation of floor spectra of the contain-ment building in nuclear power plants. The application of the single-ground-motion analysis method shall meet the requirements of envelop of the power spectral density as well as fitting of the target response spec-trum. This paper presents a generation algorithm of artificial time histories in order to meet the needs of both fitting of the target response spectrum and envelop of the power spectral density. The Fourier amplitude spec-trum is modified within the effective frequency bandwidths defined for the target response spectrum and power spectral density respectively in this algorithm, and iterations are used in order to meet the correspond-ing requirements. The numerical examples demonstrate that the artificial time history generated by this algo-rithm reaches high fitting precisions to the target response spectrum and meets the need of envelop of the power spectral density.