In the present work, a special interface between substrate and carbon films is introduced to prolong wear life of a-C:H film in high vacuum, and the optimized film exhibits an ultra-long life of 2.6×10⁵ cycles, corresponding to 9796.8 m at the normal load of 5 N. Experimental results show that gradient interlayer significantly decreases internal stress, increases adhesion strength as well as improves interface fracture toughness, and then anti-wear ability shows a corresponding improvement. This study discloses that interface design plays important roles in determining tribological behavior of a-C:H film in vacuum, which provides a novel method for developing new generation space lubrication film.