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The two Cu60Ni20Cr20 alloys with the different grain size were prepared by conventional casting (CA) and mechanical alloying (MA) through hot pressing. Effect of the grain size on electrochemical corrosion behavior of the two Cu60Ni20Cr20 alloys was also studied in solutions containing chloride ions. Results show that the free corrosion potentials of the two alloys move toward to negative values, corrosion current densities increase and therefore corrosion rates become faster with the increment of chloride ion concentrations. CACu60Ni20Cr20 alloy and MACu60Ni20Cr20 alloy have passive phenomena in 0.05mol/L Na2SO4 neutral solution, but passive phenomena become weak or disappear when the chloride ions are added. Corrosion rates of the nanocrystalline MACu60Ni20Cr20 alloy become slower than those of the coarse grained CACu60Ni20Cr20 alloy in solutions containing the same chloride ion concentrations because MACu60Ni20Cr20 alloy is able to produce large concentrations of grain boundaries and passive elements is able to diffuse quickly to form the protective film.