Abstract: The effect of trace Si(0～0.2%) on the microstructure and electrochemical performance of Al-In-Mg-Sn anode alloys used for aluminum-air batteries was studied by scanning electron microscopy, open circuit potentials, polarization curves and electrochemical impedance spectroscopy (EIS). The results show that trace Si can improve the casting character and reduce the cast defects of aluminum alloys. With the increase of Si content, the electrochemical performance of anode alloys increased first and then decreased. The best combination properties could be obtained when 0.1% Si element was added, the lowest corrosion rate(0.105 4 mg·cm-2·min-1) and the most negative OCP(-1.8 V). The discharge voltage was 1.72 V at 5 mA constant current discharge.