Abstract: This paper reviews some prevalent methods which prescribe incident rock-motion in seismic response analysis of layered soils, and we think it might be a good method to use average acceleration response spectrum in rock as characteristics of input movement for layered soils. For this reason, base on the related statistical data home and abroad, a group of typical acceleration response spectra of rock motions in accordance with different intensities （7°, 8°, 9°） and epicentral distances have then been given. Finally, this paper suggests that the Kaul's method for relating response spectrum to power spectrum can be used for producing artificial accelerograph of input movement for seismic analysis of layered soils