The InAlSb/InSb material of p-i-n structure was grown by Molecular Beam Epitaxy(MBE) on(100) InSb substrate. The current suppression effect of the barrier layer on the dark current was verified by growing a barrier layer with a wide gap between the absorber layer and the contact layer. The electrical properties of photodiode fabricated by InAlSb epitaxial material were compared with that of traditional InSb bulk material. When the external bias voltage is -0.1 V, the reverse bias current of p+-p+-n--n+ InAlSb device and p+- n--n+ InAlSb device is 3.4×10-6 A·cm-2 and 7.8×10-6 A·cm-2 at 77 K, respectively. The p+-p+-n--n+ InAlSb device suppresses the dark current at a very low level. It provides an important foundation for improving operating temperature of the infrared detector.