A　quantum　model　for　the　band　structures　of　type-II　superlattices　(taking　InAs/GaSb　for　example)　was　established　with　transfer　matrix　method　and　graphic　method,　in　order　to　identify　the　parameters　such　as　the　well　width,　the　barrier　width,　height　of　the　barrier,　response　wavelength,　etc.　Toward　different　structures,　calculations　of　the　response　wavelength　by　using　transfer　matrix　method　and　graphic　method　were　compared　with　the　real　wavelength,　and　the　virtues　of　the　two　methods　were　discussed.　By　the　comparison,　it　is　found　that　the　experiment　results　show　a　good　agreement　with　calculations.　Toward　the　superlattice,　it　shows　a　better　agreement　with　calculations　by　using　the　transfer　matrix　method,　but　graphic　method　should　not　be　used　to　calculate　the　band　structures　of　superlattices　because　of　its　limitation.