(Fe_63.3Mn₁₄Si_9.1Cr_9.8C_3.8)_99.5?xCu_xAg_0.5 (x=1, 2, 3, 4, 5, at%) alloys were prepared by water-cooled copper crucible magnetic levitation vacuum melting furnace. The effects of Cu contents on microstructure, corrosion resistance, and antibacterial performance of the alloys were investigated. The results show that the medium entropy alloys possess fcc phase after solid solution and aging treatment. With the increase in Cu content, the Cu-enriched and Ag-enriched fcc2 phase is precipitated on the fcc1 Fe-rich matrix. The corrosion resistance of the alloys in 3.5wt% NaCl solution is superior to that of AISI304. The corrosion current density first decreases and then increases, and the impedance arc radius first increases and then decreases, indicating an initial enhancement and subsequent weakening of the corrosion resistance as the Cu content increases. Moreover, the corrosion rate of the alloys in Escherichia coli suspension shows a trend of increasing first and then decreasing. When x=2 the alloy exhibits the best corrosion resistance, and there is a trade-off effect between the corrosion resistance and antibacterial performance. The fcc2 phase effectively enhances the antibacterial performance of the alloy, and the alloy of x=5 shows the optimal antibacterial rate of 99.94%.