High-entropy nitride AlCrNbSiTiN coatings were deposited by RF magnetron sputtering at different bias voltages. The structure, mechanical properties and water vapor corrosion resistance of the coatings were systematically studied. The coatings exhibit a face-centered cubic (FCC) structure, while achieving a hardness up to 35.8 GPa. The main wear mechanisms of the coatings are adhesive wear and oxidation wear. After 200 h of water vapor corrosion, the content of O in the coatings is 4.30 at.%.