Based on the orthogonal experimental design, TiCN films were deposited by magnetron sputtering on the surface of aluminum alloy. The effects of the magnetron sputtering process parameters (titanium target power, carbon target power, nitrogen to argon ratio) on the hardness and corrosion resistance of Al-Cu-Mg-Ag alloy were investigated by using salt spray corrosion, electrochemical corrosion and hardness test. The mechanism was investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the effects of magnetron sputtering parameters on the hardness of the alloy film, the maximum corrosion depth of salt spray, the corrosion current density and the adhesion of membrane and substrate of the film are in the following order:N₂/Ar > C target power > Ti target power; C target power > N₂/Ar > Ti target power; C target power > N₂/Ar > Ti target power; and Ti target power > C target power=N₂/Ar. When the power of C target is 200 W, the power of Ti target is 100 W, and the nitrogen to argon ratio is 1:40, TiCN films with excellent corrosion resistance, hardness and adhesion of membrane and substrate can be obtained.