In order to improve the hardness and wear resistance of TiN films, single-layer TiN-Cu composite films and five groups of TiCu/TiN-Cu nano-composite multilayer films with modulation period (Λ) of 5.9~62.1 nm were prepared on cemented carbide substrates by multi-arc ion plating. The microstructures and mechanical properties of the films were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), nano-indentation tester, scratch tester, friction-wear tester, and other machines. The influences of modulation period on the structures and mechanical properties of the nano-composite multilayer films were studied. Results show that compared with the single-layer TiN-Cu composite film, the TiCu/TiN-Cu nano-composite multilayer film effectively inhibited the growth of the grains, the layer was well formed, and the film was uniform and dense. The TiN grains in the film grew in face-centered cubic structure along (111) direction. With the decrease of the modulation period, the crystallinity of the film reduced, while the hardness of the film increased first and then decreased. When the modulation period was 13.7 nm, the optimal comprehensive properties were achieved, where the hardness and H³/E² value of the film reached 42.6 GPa and 0.689, the friction coefficient reached the minimum value of 0.17, and the adhesion was 49.2 N, closing to the maximum value of 53.1 N, indicating that the film possesses ideal hardness and wear resistance. Through multi-arc ion plating, the TiCu/TiN-Cu nano-composite multilayer films were prepared. By adjusting the modulation period, the mechanical properties of the films were effectively improved and the application domains were expanded.