High quality InAs/GaSb type-II band alignment superlattices infrared photodetectors with different InAs thicknesses were grown on GaSb and GaAs substrates by molecular beam epitaxy(MBE). The detection wavelengths of these InAs/GaSb SLs infrared detectors were2-5μm. The material and optical qualities of InAs/GaSb superlattices on different substrates by MBE were characterized by different measurement methods, including high resolution transmission electron microscope(HRTEM), atomic force microscope(AFM), X-ray diffraction(XRD), low temperature(LT) and room temperature(RT) photo response spectrum and LT and RT photoluminescence(PL) spectrum. Then2-5μm GaAs and GaSb based infrared photodetectors were fabricated by these InAs/GaSb type-II band alignment superlattices materials. The detectivity of the2μm GaAs based InAs/GaSb SLs photodetector is4×109 cm· Hz1/2/W at77K and that of the5μm GaSb based InAs/GaSb SLs photodetector is1.6×1010 cm· Hz1/2/W at the same temperature.