A new structure of polarized light interference interleaver is presented. The key component of the interleaver is birefringent analog waveplate. It is equivalent to a birefringent crystal. The equivalent birefringence can be much larger than that of a conventional birefringent crystal. The interleaver has the characteristics of good stability, high reliability that the general polarized light interference interleaver possesses. Moreover, it has much higher isolation and can more easily realize any size of frequency spacing. An interleaver with the frequency spacing of(50 GHz) is designed. The flatness width of passband and stopband are both greater than 1/5 period, and the channel isolation is -30 dB. Several parameters in practical applications of this device, such as insertion loss, polarization dependent loss and cost are analyzed and discussed as well.