Pitting behavior of AZ63 magnesium alloy in sodium chloride solution was investigated by weight-loss measurement , linear sweep voltammetry ( LSV) , staircase voltammetry ( SCV) and electrochemical impedance spectroscopy ( EIS) .Influence of trisodium phosphate and sodium fluoride on the corrosion inhibition of AZ63 magnesium alloy was observed. The surface morphology of the alloy was observed with scanning electron microscope ( SEM) . The results show that higher Cl concentration results in higher pitting corrosion tendencies. However, the values of E_b-E_rpdecreased gradually when Cl concentration went beyond 5 . 5 % . The pitting corrosion tendencies of the alloy in high sodium chloride concentration solution were greater than in lower concentration solution. The corrosion rate of magnesium alloy could decrease by using trisodium phosphate as corrosion inhibitor, and pitting potential E_bincreased with the increasing of PO^3-₄concentration. When the mass fraction of trisodium phosphate was 2 . 0 % , the inhibitive efficiency of AZ63 magnesium alloy was 92 . 8 % . The corrosion rate of AZ63 magnesium alloy decreased, and the resistance value was 3092 Ω·cm²when 0 . 16 % sodium fluoride and 2 . 0 % Na₃PO₄ were used as compound agent .