In order to improve the surface quality of die steel,CrAlN films were deposited on H13 die steel by multi arc ion plating technology.The effects of surface nitriding treatment of die steel substrate on the surface morphology,hardness,adhesion,oxidation resistance and friction and wear properties of the deposited films were investigated.The results show that the surface of CrAlN coating prepared before and after surface nitriding treatment of the substrate is uniform and dense,with a small amount of large particles.The surface of CrAlN coating shows the preferred orientation of CrN(200) surface,and the preferred orientation of CrAlN coating prepared after nitriding treatment is stronger.After surface nitriding treatment,the hardness of H13 steel substrate is significantly improved,which can support the prepared coating,reduce the tendency of cracks,increase the critical load of cracks in the coating,and improve the film substrate bonding force of the coating.Compared to the CrAlN coating prepared without nitriding treatment on the substrate surface,the CrAlN coating prepared after surface nitriding on the substrate has higher hardness and adhesion,better friction and wear performance,and the high-temperature oxidation resistance is significantly enhanced.