The epitaxial growth of GaSb on GaAs substrate was studied by using interface mismatch arrays （IMF）. The effects of growth temperature， Sb： Ga effective atomic flux ratio， thickness of AlSb transition layer and GaSb epitaxial layer on the structural quality of the material were studied. High Resolution X-ray Diffraction （HRXRD） study shows that the FWHM of the diffraction peak measured by HRXRD was very sensitive to the changes of above parameters， while the effective atomic flux ratio （EFF） of Sb： Ga was the most important factor. The FWHM value of GaSb diffraction peak changes slightly with the increase of thickness， but the structural quality of GaSb layer improves with the increase of thickness. The results show that the optimum growth temperature of GaSb is 515℃， the optimum thickness of AlSb transition layer is 5 nm. The 10 nm thick GaSb epitaxial layer was prepared and characterized specifically. The results show that the FWHM value of the diffraction peak is only about 15 arcsec， which is equivalent to that of commercial GaSb substrate. The electron mobility of the quantum Hall device is as high as 1.5×10⁵ cm²/Vs at 1.8 K under zero bias， which attains to the level of device performance on GaSb substrate.