Hydrogenated nitrile butadiene rubber (HNBR) often suffered from high friction and severe wear due to its viscoelasticity under dynamic sealing conditions. To improve its tribological performance, diamond-like carbon (DLC) films with varying Ti interlayer thicknesses were deposited on HNBR by unbalanced magnetron sputtering. Effect of Ti interlayer thickness on the microstructure, mechanical properties, and tribological performance under different applied normal loads of the DLC films on HNBR was systematically investigated. The results revealed that the DLC films exhibited a microscale crack-like network morphology, and the density of crack-like networks increased with the increase of the Ti interlayer thickness. The increasing Ti interlayer thickness effectively reduced the residual stress in the film and enhanced interfacial adhesion to the HNBR substrate. Raman and XPS analyses revealed that a thicker Ti interlayer promoted the formation of sp 3-hybridized carbon bonds, which contributed to an increase in film hardness from 14.26 GPa to 19.35 GPa. Cross-sectional morphologies showed no delamination between the Ti interlayer and the DLC film, demonstrating good adhesion. Tribological tests demonstrated that the DLC films with varying Ti interlayer thickness exhibited superior tribological performance under low loads; however, brittle fractures occurred in some films under high applied loads, leading to wear failure. Notably, DLC films with a Ti interlayer thickness of approximately 390 nm maintained stable rubbing performance with friction coefficient around 0.3 under different loads. This enhancement resulted from the load-bearing capacity of the Ti interlayer, which supported the mechanical integrity of the DLC film and facilitated better interfacial bonding. Moreover, a thicker Ti interlayer enhanced the film's ability to deform synchronously with the rubber substrate, thereby delaying film failure and improving wear resistance and friction reduction. These findings confirm that the DLC films deposited on HNBR exhibit excellent mechanical and tribological performance, offering a theoretical basis for enhancing the durability of rubber sealing in offshore wind power equipment.