Diamond-like carbon coatings have been used as solid lubricating coatings in vacuum technology for their good physical and chemical properties. In this paper, the hybrid technique of unbalanced magnetron sputtering and plasma immersion ion implantation (Pill) was adopted to fabricate diamond-like carbon-based functionally gradient film, N/TiN/Ti(N,C)/DLC, on the 304 stainless steel substrate. The film was characterized by using Raman spectroscopy and glancing X-ray diffraction (GXRD), and the topography and surface roughness of the film was observed using AFM. The mechanical properties of the film were evaluated by nano-indentation. The results showed that the surface roughness of the film was approximately 0.732 nm. The hardness and elastic modulus, fracture toughness and interfacial fracture toughness of N/TiN/Ti(N,C)/DLC functionally gradient film were about 19.84 GPa, 190.03 GPa, 3.75 MRa.m1/2 and 5.68 MPa-m1/2, respectively. Compared with that of DLC monolayer and C/TiC/DLC multilayer, this DLC grad Diamond-like carbon coatings have been used as solid lubricating coatings in vacuum technology for their good physical and chemical properties. In this paper, the hybrid technique of unbalanced magnetron sputtering and plasma immersion ion implantation (Pill) was adopted to fabricate diamond-like carbon -based functionally gradient film, N / TiN / Ti (N, C) / DLC, on the 304 stainless steel substrate. The film was characterized by using Raman spectroscopy and glancing X-ray diffraction (GXRD), and the topography and surface roughness of the film was observed using AFM. The mechanical properties of the film were evaluated by nano-indentation. The results showed that the roughness of the film was about 0.732 nm. The hardness and elastic modulus, fracture toughness and interfacial fracture toughness of N / TiN / Ti (N, C) / DLC functionally gradient film were about 19.84 GPa, 190.03 GPa, 3.75 MRa.m1 / 2 and 5.68 MPa-m1 / 2, respectively. Compared with that of DLC monolayer and C / TiC / DLC multil ayer, this DLC grad