With the increase in firing rate and ammunition volume of body barrel firing weapons, the mechanical characteristics of the bore plating have put forward higher requirements, making the traditional electrochromic plating process has gradually failed to meet its needs. In this paper, 20 μm and 50 μm metal chromium coatings are prepared by vacuum arc ion plating technology on the substrate surface of PCrNi3MoV alloy steel (special steel) by the same process, and their surface morphology, mechanical and tribological properties are tested. By studying the effect of coating thickness on morphology, it is found that thicker coating plays a positive role in reducing surface defects and improving surface quality. By testing mechanical and tribological properties of the substrate surface before and after coating, it is found that the friction coefficient of the coating is between 0.32 and 0.42, which is 0.02 lower than the current Cr coating prepared by arc ion plating technology in China (0.35~0.45). The bonding strength of the coating with the substrate is 45.3 N, and the microhardness reaches 15.01 GPa. In the process of comparing the plating thickness on the surface wear resistance, it is found that the deposition of thicker plating is beneficial to the improvement of wear resistance, in which the 50 μm thick Cr plating has only slight wear on the surface after 1 800 times, and the wear rate is 0.000 13 mm3/(N·m). Compared with the uncoated substrate, the wear resistance is improved by 75.93%. This will be of great significance in extending the service life of the artillery barrel and promoting the development of protective coatings.