Abstract: WCN nano-composite films were fabricated by multitarget reactive magnetron sputtering technology at different C target powers which were proportional to carbon contents. The properties and microstructure of these films were investigated by X-ray diffraction, scan electron microscopy, nano-indentor and high-temperature tribometer. And the effects of carbon content on the properties of films were studied. The results show that a new phase of WCN grew in the film which had single phase of WN and the lattice constant of the film increased, when the power of C target (C content) increased. The hardness, elastic modulus of composite films rose up first than dropped down with the carbon content increasing, and the highest values of 36.70 GPa for hardness and 409.16 GPa for elastic modulus were gotten when the power of C target was 120 W. The friction coefficient and wear rate for composite films decreased and then increased with increasing of C content at room temperature. The friction coefficient was higher at high temperature than room temperature. Abrasive wear was the main wear mechanism for the films.