Abstract: Optical properties of N-doped anatase TiO2 films prepared by N ion implantation have been studied. At first, TiO2 films were prepared by RF magnetron sputtering at different substrate temperatures. Then N ion implantations in the films were conducted at fluences of 5×1016, 1×1017 and 5×1017/cm2, respectively. X-ray diffraction(XRD) results show TiO2 is anatase. X-ray photoelectron spectroscopy(XPS) results reveal that N ions interact with TiO2 particles and form TiOxN2-x compound, which leads to the shift of the absorption edge. Simultaneously, the irradiation defects caused by N ion implantation also increase the absorption intensity of TiO2 films in the range of UV-Visible light．