In　this　paper,　a　novel　design　method　used　for　the　birefringent　interleaver　is　presented,　which　is　based　on　Harris　systematic　design　theory　with　some　improvements　in　respects　of　the　approximation　of　the　number　of　crystal　used　and　the　dispersion　compensation　of　crystal　materials.　In　our　method,　as　optimal　designing,　the　required　frequency　response　of　interleaver　as　the　target　function　is　specified　in　first　step　of　calculation,　and　some　basic　design　parameters　such　as　the　number　of　crystals　and　rotation　angles　of　each　element　will　be　automatically　obtained.　This　design　method　is　flexible　for　different　crystal　materials　and　is　extensible　for　the　consideration　of　the　manufacture　tolerances　and　the　temperature　compensation　of　crystal.　As　a　design　example,　simulation　results　are　presented　and　relative　analyses　are　taken.