The characteristics of ion beam sputtered metallic oxides deposited in high vacuum are analyzed by X-ray diffractometer. atomic force microscopy, spectrophotometer and ellipsometer. The metallic oxide thin films include aluminum oxide, niobium oxide, silicon oxide, tantalum oxide, zirconium oxide, and titanium oxide. The structure, surface morphology and optical constant are described. An oxide film with low surface roughness, low extinction coefficient and high packing density is crucial for an optical application. We found that to make such a high quality film there is an optimum deposition condition and an optimum post-baking temperature. Moreover, the optimum deposition condition and the optimum post-baking temperature are different for different metallic oxides.