Abstract: The effect of NaCJ on the corrosion behavior of API P105 steel in the CO₂-saturated solution was studied by electrochemical impedance spectrum(EIS) and polarization measurement. The results showed the increase of NaCl concentration decreased the the corrosion rate of the steel, which could be attribulted the decrease of hydroxide ion concentration and the dissolution of CO₂, and the adsorption of Cl^- obeyed the Temkin isotherm.