In this study, the surface modification of the vacuum arc deposition (VAD) CrN coatings are performed using atomic layer deposition (ALD) technology. The influence and mechanism of ALD technology on the phase structure, surface and section profile, adhesion, hardness and surface roughness of CrN-VAD coating were studied, respectively, through XRD phase analysis, SEM structure characterization, mechanical properties and roughness test. The XRD results show that the ALD-modified CrN coating consists of a single phase with the strong preferred orientation. The full width at half maximum of diffraction peak becomes broad indicates that the grain is significantly refined. It can be inferred by the SEM results that the coating is more dense, its cross-section is arranged in a staggered disorder manner, and the surface defects of the original VAD coating are sealed and mitigated. Test results on mechanical properties show that the hardness of the sample after ALD modification greatly increased from 31 to 34.4 GPa, and the coating-matrix bonding force increased from 95 to 104 mN. After ALD modification, the surface roughness reduced from 34.4 to 17.7 nm. The ALD technology can be used to improve wear, corrosion, and other properties of CrN-VAD coatings, extending their service life.