Abstract: In terms of the given ESA power spectral density (PSD) function characteristics, a FIR digit filter was designed based on finite unit impulse response. The filter amplitude-phase characteristics that completely met the conditions of given power spectral characteristics were obtained by changing parameters of FIR digit filter. The random vibration time signal was generated with the white noise as input of the filter. Furthermore, autoregressive parameter model was used to estimate and validate the power spectrum of obtained time signal. The results show that the error between two spectral curves are in the range of permits, and the random vibration time signal obtained using presented method could completely meet the requirements of simulation and test.