Based on optical rotatory dispersion effect, the principle of the multistage quartz crystal filter was theoretically analyzed by using Muller matrix and Stokes parameter. The wavelength of the main peak and full width at half maximum (FWHM) of peaks of the multistage optical filter were deduced. The characteristics of the single and multistage quartz crystal optical filters were systematically investigated by the spectrometer, and the experimental results verified the theoretical analysis. The results proved that, compared with the single quartz crystal optical filter, the FWHM can be effectively compressed by multistage quartz crystal optical filter, and the compression ability increases with the increase of the stage number.