CrMoSiCN nanocomposite coatings with a low C content were prepared on Ti-6Al-4V using an unbalanced magnetron sputtering system, and their corresponding microstructures, mechanical properties, and tribocorrosion performance were evaluated in detail. The results revealed that the CrMoSiCN coating had a compact nanocomposite microstructure consisting of CrN and Mo₂N nanocrystallites, (Cr, Mo)N solid solution, and Si-C-N amorphous phases. Moreover, the coating exhibited superior mechanical properties with a hardness of 28.6 GPa and an elastic modulus of 273 GPa, owing to the solid solution strengthening effect. The tribocorrosion test results showed that the dominant failure of the Ti-6Al-4V alloy was caused by the corrosion contribution to wear behaviors (synergistic effect). The CrMoSiCN nanocomposite coating could effectively alleviate the material loss caused by the synergistic effect of corrosion and wear behaviors, leading to pure wear behaviors during the entire tribocorrosion process. The corresponding tribocorrosion mechanisms under the open circuit potential and dynamic polarization conditions were discussed in terms of their tribocorrosion behaviors.