The detection accuracy will be reduced due to the disturbance of noise and outside to original data. It is necessary to apply the band-pass filter in the wavefront power spectral density(PSD) analysis to handle this problem. The effective filter can reduce the effect of outside band noise and avoid frequency aliasing. The infinited impulse response band-pass filter(IIR) and the finited impulse response band-pass filter(FIR) were designed in this experiment. Characters of the two filters were compared by simulating analyse. And the result indicates that the better evaluation would be obtained if the FIR filter is used in the wavefront PSD which is used in testing large aperture components.