In As/Al Sb tw o-dimensional electron gas ( 2 DEG) structures w ere successfully grow n by M BE equipment. 2 DEG characteristics of samples w ere improved by optimizing the the thickness of Al Ga Sb buffer layer, the thickness of In As/Al Sb interface layer, and the thickness of Al Sb spacer. The In As/Al Sb 2 DEG structure sample w ith an electron mobility of 20 500 cm2/V·s and a sheet electron density of 2. 0 × 1012/cm2 w ere achieved w hen the thickness of Al Sb spacer is fixed at 5 nm. It provides a reference for the research and fabrication of In As/Al Sb HEMT.