This paper reports a surface and interface study of indium antimonide epitaxially grown on gallium arsenide using metalorganic magnetron sputtering technique. X-ray photoelectron spectroscopy analysis shows that the original surface of InSb is composed of InSb, In2O3, and Sb2O3, and the binding energy of Sb 3d(5/2) decreases when an antimony atom is surrounded by more indium atoms. The interdiffusion phenomenon is studied by both Anger electron spectroscopy depth profiling and Rutherford backscattering spectroscopy, the results of which are in good agreement. The width of the interdiffusion region is around 900 +/- 100 Angstrom, and independent of epilayer thickness. X-ray diffraction study indicates that the crystallinity of the InSb epilayer becomes better with the increase of epilayer thickness. It is also demonstrated that the crystal orientation relationship between the InSb epilayer and GaAs substrate is (100) InSb//(100) GaAs, and the (100) crystal planes of InSb and GaAs are parallel to the macro-surface of the InSb/GaAs heterostructure.