<p>In this research, a series of high entropy alloys (HEAs) with varying compositions of FeCrMnAlCu_x (x = 0, 0.5, 1.0, 1.5, 2.0) were synthesized using the vacuum arc melting technique. The results show that the addition of Cu element is beneficial to the formation of FCC phase in the alloys. With an increase in Cu content, the corrosion resistance of FeCrMnAlCu_x HEAs decreases. When x = 0, the lowest corrosion current density is 7.225 × 10^–7 A/cm², and the corrosion potential reaches its maximum value of −0.475 V_SCE. When x = 2.0, the corrosion potential of the alloy reaches its minimum value of −0.649 V_SCE, and the corrosion current density reaches its maximum value of 8.609 × 10^–6 A/cm². The addition of Cu element leads to selective corrosion between interdendritic, which is related to the weak protective passivation films formed by the Cu-rich phase.</p>