This study utilized cathodic arc deposition technology to coat Ti-Al-N hard films on AISI 4340 alloy steel. Composition, morphology, and structure of the coatings were analyzed using EPMA, FESEM, XRD, and TEM. Both wear tests and polarization tests were conducted to determine the abrasion and corrosion properties of the steel before and after coating. The results showed that a specific (Ti, Al)N nanostructured multilayer was synthesized smoothly. The multilayer consisted of 10 nm-TiN and 15 nm-TiAlN interaction layers. The coating not only greatly reduced the friction coefficient of AISI 4340 alloy steel from 0.81 to 0.45, but also provided an effective improvement in corrosion resistance.