Abstract: A new method which improves the fitting accuracy of artificial time history of ground motion to the target response spectrum by superimposing narrowband time histories in the time domain is proposed. Firstly, the method utilizes the traditional one, which modifies the Fourier amplitude spectrum in the frequency domain, to generate an initial time history of acceleration compatible with the specified peak ground acceleration, the target response spectrum and the prescribed intensity envelope. And then based on the inversion formula of the seismic input to linear single-degree-of-freedom system, the method further adjusts the initial time history to improve its fitting precision to the target spectrum by superimposing narrowband time histories in the time domain. Numerical examples demonstrate that the artificial ground shaking time histories obtained by the proposed algorithm boast high fitting precisions to the target spectrum.