MoSiCN films were deposited on the silicon and stainless steel wafers by reactive magnetron sputtering under a bias voltage of −100 V. The structures and mechanical properties of the MoSiCN films were investigated by XRD, XPS, TGA and Nano–indenter, scratch test. It was found that Si contents were closely correlated to the structures of the anocomposite films. We have found that nanocomposite coatings are composed of nanocrystalline MoCNx in a matrix of amorphous SiCN. The hardness of as–deposited films exhibits a maximum hardness at 30 GPa, as evaluated by nanoindentor XP. The oxidation resistance temperature of the film is about 1100 ℃, according to the TGA measurements. Salt spray test of the MoSiCN coatings was also carried out, which exhibited a corrosion time of over 150 h.