In this study, FeCr?MnAlCu (x=0, 0.5, 1.0, 1.5, 2.0) high-entropy alloys were fabricated using vacuum arc melting and the corrosion behavior of the alloy in 3.5 wt.% NaCl solution at room temperature was investigated by means of electrochemical dynamic potential polarization curves and immersion experiments. The microstructure results show that Cr₀ alloys formed a BCC phase structure, while Cr_0.5 to Cr_2.0 high entropy alloys formed a mixed FCC+BCC dual-phase structure. The corrosion results show that the corrosion resistance of the high-entropy alloy increases with the increase of Cr content. Among them, the Cr_2.0 high-entropy alloy exhibited the best corrosion resistance with the highest selfcorrosion potential (E_corr = - 0.354 V vs Ag/AgCl) and the smallest self-corrosion current density (I_corr = 1.991×10_-6 ^A?cm_-2) and the smallest corrosion rate (0.0292 mm/a). The XPS fitting results show that a composite passivation film of oxides and hydroxides was formed on the surface of the corroded high-entropy alloy, and the Cr₂O₃ content increases with the increase of Cr content, which effectively improves the stability and protective properties of the passivation film.