Abstract: The electrochemical corrosion behavior of CuNi₂Si alloy was investigated in NaCl solution at different pH values by electrochemical workstation. The results show that the corrosion current density decreased with the increase of pH and the corrosion resistance was enhanced for CuNi₂Si alloy in NaCl solution at different pH values. The corrosion process was mainly controlled by the diffusion of dissolved oxygen and hydrogen ion between liquid phase and metal interface. It was shown that free corrosion potential did not reflect the corrosion resistance of CuNi₂Si alloy through the Evans diagram and the calculation analysis of corrosion mass loss. Corrosion current density could be used as a criterion for corrosion resistance under specific condition.