Abstract: To improve the corrosion resistance of bipolar plates of proton exchange membrane fuel cell (PEMFC) in the actual vehicle operation, the CrAlCN coating was deposited on 316L stainless steel substrate by magnetron sputter technology. Field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical workstation were used to investigate the microstructure, chemical bond type and corrosion resistance of the CrAlCN coating. The results show that the CrAlCN coating was mainly composed of Cr7C3, CrN, AlN and metal oxide phases. The coating structure was dense and had no obvious defects. CrAlCN coating provided excellent corrosion protection for 316L stainless steel bipolar plates under cyclic potential polarization and long-term immersion conditions, indicating that CrAlCN coating has great application potential on bipolar plates.