Abstract: In this paper,2024 aluminum alloy was friction stir welded.In the ambient mixed solution of 0.2 mol/L NaHSO₃ and 0.6 mol/L NaCl with the addition of different concentrations of sodium molybdate(Na₂MoO₄),the effect of Na₂MoO₄ on the corrosion behavior of the friction stir weld and 2024 aluminum base metal were evaluated with static weight loss experiments,potentiodynamic polarization curve test and electrochemical impedance spectroscopy(EIS).The results indicated that Na₂MoO₄ acted as an effective inhibitor,especially,the inhibition efficiency of the weld was higher than that of the base metal,and the inhibition efficiency increased with increasing concentration of Na₂MoO₄.The polarization data showed that Na₂MoO₄ behaved as an anode passivation inhibitor.A mechanism was proposed to explain the experimental results.