In this research,stainless steel bipolar plates for proton exchange membrane fuel cell(PEMFC)have been treated by an atmospheric plasma surface modification technology.The chemical composition and thickness of the oxide film formed by plasma are conducted to verify by Auger electron spectroscopy(AES).Pitting resistance,potentiodynamic polarization curves and electrochemical impedance spectroscopy(EIS)are measured to evaluate the corrosion mechanism and electrochemical properties.The results show that the treated plates have a much thicker oxide film which leads to higher pitting potential,improved corrosion rate,less and smaller pitting holes than those without treatment.The stable chemical and electrochemical properties of the treated stainless steel bipolar plate indicate the stabilization of cell performance and longer service life. In this research, stainless steel bipolar plates for proton exchange membrane fuel cell (PEMFC) have been treated by an atmospheric plasma surface modification technology. The chemical composition and thickness of the oxide film formed by plasma are conducting to verify by Auger electron spectroscopy (AES Pitting resistance, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) are measured to evaluate the corrosion mechanism and electrochemical properties. The results show that the treated plates have a much thicker oxide film which leads to higher pitting potential, improved corrosion rate, less and smaller pitting holes than those without treatment. The stable chemical and electrochemical properties of the treated stainless steel bipolar plate indicate the stabilization of cell performance and longer service life.