Abstract: Y has the effect of oxygen barrier and fine crystal along the grain boundary, which make CrAlYN film layers widely used in the engineering field of tools, molds and high-temperature parts, etc. CrAlYN films were prepared on W18Cr4V substrates by magnetron sputtering. The high temperature oxidation experiments were conducted at 700 ℃, 800 ℃,900 ℃ and 1000 ℃. The morphology, phase structure, chemical composition, nanohardness, elastic modulus and specific wear rate of the film changing with the temperature were characterized by XRD, SEM/EDS and nano-mechanical system（G200）. The results show that compared with the W18Cr4V,the hardness and modulus of the film layer are much higher and the specific wear rate is much lower. From 700 ℃ to 1000 ℃, the hardness and modulus of the film layer decreases from 21.5GPa and 298.3 GPa to 6.47 GPa and 172.0 GPa. On the whole, the trend of specific wear rate is rising, where the specific wear rate at 800 ℃ is 11.1 times higher than that at 700 ℃, and the specific wear rate at 1000 ℃ is 1.25 times higher than that of at 900 ℃. The increase of specific wear rate and the reduction of thermal stability attribute to the combined effect of the growth of oxidation on the surface of film layer.