Abstract: Using TiCl₄,O₂ and NH₃ as the precursors,N-doped titanium dioxide films were prepared by APCVD.According to the results from SEM,X-ray diffraction（XRD） and the UV-VIS absorption spectrum,it is found that a new phase of Ti₄O₇ is formed in the thin film after nitrogen doping and the crystal transformation from anatase to rutile is inhibited.As well,a red drift of the absorption edge from 365.8nm to 402.6nm exists in the N-doped TiO₂ films and the visible-light induced photocatalysis and hydrophilicity are both enhanced.