Abstract: High entropy alloys FeCoCrNiMnCx(x is 0, 0.1, 0.2, 0.3, 0.4) with different carbon contents were prepared by cold crucible smelting method, and effects of carbon content on microstructure, mechanical properties and corrosion resistance of the alloys were studied. The results show that high entropy alloys FeCoCrNiMnCx had the typical dendrite structure. With the increase of carbon content, the number and size of precipitate Cr7C3 increased, the hardness increased and the strength increased and then decreased. The maximum tensile strength of the alloy was up to 665 MPa when x=0.3. In 3.5wt% NaCl solution, with the increase of carbon content, the corrosion current density of the alloys decreased, and the alloy FeCoCrNiMnC0.4 owned the best corrosion resistance.