Abstract: The present invention discloses a type-II superlattice photodetector with a low-thickness absorption region. The absorption region of the type-II superlattice photodetector includes an In(Bi)As layer and a Ga(N)Sb layer. The Bi element content in the In(Bi)As layer is less than 10%, and the Bi element content in the Ga(N)Sb layer is less than 5%. The present invention forms an InBiAs layer and a GaNSb layer by condensing the Bi element into the InAs layer and condensing the N element into the GaSb layer of a traditional InAs/GaSb type-II superlattice photodetector. Therefore, without changing the cut-off wavelength and performance of the detector, periodic and total thicknesses of the type-II superlattice photodetector material can be effectively reduced, and both costs of material use and molecular beam epitaxy can be reduced. In addition, the overall absorption coefficient of the material can be improved, and the volume of the entire device can be reduced.