On the basis of research of the ordinary double pass polarization interference filter with identical thickness retarders, the new type double pass polarization interference filter is deduced in theory. The spectral and angle characteristics of three types of polarization interference filters are analyzed. The result shows that the new type double pass polarization interference filter has better spectral characteristics in practice can reduce the number of retarders, and is expected to be used extensively in color separation and recombination system of liquid crystal on silicon projector.