•Ti buffer layer was employed to release residual stress of TiN/TiCN films.•Surface chemical composition of films was measured.•Phase structure and residual stress of TiN/TiCN multilayer were determined and analyzed.•Surface topography and cross-section morphology were exhibited by SEM.•Optimal reaction gas ratio obtained for reduce residual stress.TiN/TiCN films were prepared on AZ31 by physical vapor deposition. Structural features and residual stress were determined by X-ray fluorescence (XRF), scanning electron microscopy (SEM) and based on the grazing incidence X-ray diffraction (GIXRD), respectively. Results show that films have (111) preferred orientation. With a increasing of the reaction gas ratio, the C + N and Ti content increases first then decreases, and reach at the maximum value when the gas ratio is 15/5/3. Film have uniform thickness, and the hole shape defects appears in partial film and non-uniformly distribute on the surface of the film. The residual stress was tensile stress, and the residual tensile stress value decreased with the increase of the reaction gas ratio.