Abstract: A series of titanium oxide thin films have been synthesized on silicon wafers by ion beam enhance deposition at different O₂ pressure. X-ray Photo-electron Spectroscopy, X-ray diffraction (XRD), glancing angle diffraction and Rutherford backscattering spectroscopy(RBS) were used to analyse the composition, structure and orientation of the film. It was found that: 1) The film is polycrystal-line with Ti²⁺, Ti³⁺, Ti⁴⁺ coexist. 2) When O₂ pressure is lower than 8.4× 10^-4 Pa, the main composition of the film is TiO that preferred orientation changed from (220) to (031) with the increase of O₂ pressure. 3) When the O₂ pressure is above 8.6× 10^-4 Pa, rutile TiO₂ with a preferred orientation of (100) is foundto be the major composition of the film.