The invention discloses an Al-TiC composite film and a preparation process thereof. The Al-TiC composite film is prepared from 0.1 at.%-11 at.% of TiC and the balance Al, and a double-ultra supersaturated solid solution has displacement solid solution and interstitial solid solution characteristics. The preparation process of the Al-TiC composite film includes the steps of magnetron sputtering andannealing treatment. The step of magnetron sputtering includes the procedures that the surface of a stainless steel substrate is pre-treated, the stainless steel substrate is subjected to argon plasma sputtering cleaning, and the Al-TiC composite film is vapor-deposited on the surface of the stainless steel substrate. According to annealing treatment, vacuum annealing is carried out at the temperature of 250 DEG C. The Al-TiC composite film is high in strength and hardness, good in high-temperature stability and high in production efficiency, and can be used for coating materials of specificparts.