Composite TiO x N y films were synthesized with pulsed bias arc ion plating from two Ti target evaporators in a gaseous mixture of Ar, N 2 and O 2. With the substrate bias varying from 0 to −700 V, the structural, compositional, mechanical and optical properties of the films were characterized with X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), wear tests and UV–VIS absorption spectra. XRD and XPS results show that deposited at a substrate bias of −100 V, the film crystallized in a mixture of Anatase and Rutile TiO 2 phases with O locations partly substituted by N atoms. The threshold wavelength of optical absorption shifts from 367 to 400 nm after N doped, which is related with band gap narrowing cased by N doping. The wear tests indicate that friction efficient first decreases, then increases as the substrate bias goes up. The films deposited at a bias of −300 V exhibit the lowest friction efficient, less than 0.15. For the films on steel substrates, the TiO x N y films deposited at −300 and −500 V exhibit the highest adhesion strength and nano-hardness, respectively.