In order to improve the absorption of oxide thin films in wavelength of deep ultraviolet (DUV), Al2O3 and SiO2 thin films for DUV are fabricated by ion beam sputtering (IBS). The refractive index n and extinction coefficient k of the thin films are obtained using spectrophotometry and ellipsometry in the 190~800 nm. High reflectance (HR) Al2O3/SiO2 coatings are designed and produced at 193 nm. After annealing, the optical loss of the coating becomes smaller. The scattering loss is much lower than the absorption loss which occupies the main role of the total loss. Oxide coatings deposit according to optimized process can have more suitable optical properties at DUV. The optical loss reduces so considerable that the reflectance of HR coatings reach more than 96% at 193 nm.