Silver has low shear strength, which can reduce the friction and wear of the coating. TiN/Ag composite coatings were successfully prepared on SUS304 stainless steel substrates by multi-arc ion plating. Microstructure and mechanical properties of TiN/Ag coatings were analyzed by a scanning electron microscopy, nano-indentation and RST3 scratch tester. Tribological properties of TiN/Ag coatings were evaluated by CSM (atmosphere) and HVTRB (vacuum) tribometer. TiN/Ag coatings have compact structure and Ag has obvious grain strengthening effect. The results showed that the TiN/Ag coatings with a thickness of 1.2 μm and hardness of 28.4 GPa has a uniform and compact structure. The Tribological test shows that the friction coefficient in vacuum environment is much lower than that in atmospheric environment. The main wear mechanism in atmospheric environment is adhesive wear and abrasive wear, while in vacuum environment it is mainly mechanical polishing and tribolayers. The friction experiments of TiN/Ag coatings under different loads in vacuum environment show that the friction coefficient is as low as 0.07 under 1 N load, and slight wear occurs on the coatings; under the condition of 3 N load, the mechanical energy and thermal stress make the Ag diffuse at the friction interface, and the friction coefficient increases rapidly to about 0.42; the friction coefficient fluctuates obviously under 5 N, and increases with the increase of sliding time. The highest coefficient is 1.0, and the surface of coating softens to form furrow effect, which leads to coating failure. Conclusion The doping of Ag in the TiN/Ag coating can significantly reduce the internal stress of the coating, inhibit the extension of microcracks during the friction process, and improve the tribological properties of TiN hard coating under an appropriately low load in a A vacuum environment.