In this study, Ti-Al-Si-Cu-N nanocomposite films with different Cu contents were deposited on AISI-304 stainless steel by DC reactive magnetron sputtering. Both Ti-Al-Si-N and Ti-Al-Si-Cu-N nanocomposite films were oxidized at 800℃ to investigate the influence of Cu content on the microsturcture and high temperature oxidation resistance by means of scanning electron microscope(SEM), energy disperse spectroscopy(EDS), X-ray diffraction(XRD), nanoindentation tester and a home-made indentation system. The results indicated that with increasing copper content in the films, the micropores disappeared from the surface of Ti-Al-Si-N nanocomposite film and the compact films were obtained. A reduction of the grain size and a change of the (111) preferred orientation to (110) were observed. The microhardness of films increased from 14.76 GPa to 19.42 GPa. The elasticity modulus of Ti-Al-Si-Cu-N films with 1.72 at.% Cu content had the minimum value of 104.5 GPa. The incorporation of copper at high temperature had two effects, one was that the diffusion rate of Al element was advanced another was the crack of oxide layer was induced and the micropores were produced. Ti-Al-Si-N films had a better oxidation resistance than that of the films added Cu element.