TiO2 thin films of different N-doped quantity and different current density were deposited on medical glass slide by arc ion plating. Film structure, surface morphology and optical properties were measured with XRD, SEM and UV-VIS transmittance spectroscope. Photo-catalytic performance of the films was evaluated by degradation methyl orange. The current density, O2 partial pressure and N2 partial pressure were varied in order to determine their effect on the properties of TiO2 films. The study got the best doped process (current 50A，O2 50sccm, N2 250 sccm, Ar 20sccm). In these experimental conditions, the absorption edge successfully moved to 510nm, the as-deposited TiO2 films structure was composed with anatase and rutile. The annealing treatment made the crystal microscopy more obviously. The N-doped TiO2 film not only reduced the UV catalytic performance , but also extended the catalytic properties to the sun light.