N-doped TiO2 films were prepared by using N ion beams to bombard TiO2 films surface. By controlling the metal ultrahigh vacuum gat valve, only the N ion beams working pressure was adjusted from 0.1 to 0.9 Pa, with the step size of 0.2 Pa. The composition, chemical bond structure, and optical properties of N-doped TiO2 films were investigated. The result indicated that with increasing the ion