Diamond-like carbon (DLC) films are expected to be one of the ideal surface protective coatings for aluminum alloy due to their high hardness, good chemical inertness and excellent friction properties. The physical vapor deposition (PVD) technology used to prepare DLC films was compared with the traditional surface modification techniques of aluminum alloy. The latest research achievements for improving the mechanical and tribological properties of aluminum alloy by DLC protecting films were summarized. Meanwhile, the obstacles in the harsh applications such as poor resistance to plastic deformation and low adhesion between the film and substrate were generalized. By analyzing the unfavorable factors of high-performance DLC film deposited on aluminum alloy substrate, it was found that the low interface chemical bonding strength, high residual stress and the structural system limitation of soft matrix/hard film were the main causes of the above problems. On the basis of this, the measures taken by the domestic and foreign researchers to improve the adhesion between DLC film and aluminum alloy and corresponding results were presented, including surface treatment for strengthening mechanical properties and reducing surface defects, preparing single-layer or multi-layer interlayers to reduce the difference of the structure and properties between DLC film and aluminum alloy matrix by PVD or other surface modifying methods, and reducing the residual stress by controlling the composition and structure of DLC film. Finally, the future development trends of DLC protective film on aluminum alloy substrate are proposed.