We　investigate　two　passivation　methods　for　long-wavelength　infrared　type-II　InAs/GaSb　superlattice　(T2SL)　photodiodes　with　the　P　pi　BN　structure　containing　an　InAs/AlSb　hole　barrier　layer.　In　order　to　eliminate　the　surface　defects　of　T2SL　better　to　further　reduce　the　surface　dark　current,　anodic　vulcanization　and　SiO2　composite　passivation　method　is　adopted　to　optimize　the　original　SiO2　passivation　method.　At　77　K,　the　I-V　curve　of　the　devices　under　the　two　passivation　methods　are　obtained.　Compared　with　passivation-only　SiO2,　the　dark　current　density　of　the　anode　sulfide　and　SiO2　composite　passivation　detector　is　reduced　by　one　order　of　magnitude,　and　the　surface　resistivity　is　effectively　improved　by　an　order　of　magnitude.　Additionally,　the　composite　passivation　method　not　only　improves　the　uniformity　of　the　device,　but　also　prevents　the　peeling　of　the　S　layer　to　improve　the　quality　of　passivation.　This　work　offers　a　stable　and　high-quality　passivation　method,　and　it　could　be　popularized　passivation　in　the　field　of　optics,　electronics,　optoelectronics,　and　switching　devices.