The effects of 0.01 wt.% Ga on microstructure and electrochemical performance of Al-0.4Mg-0.05Sn- 0.03Hg anodes in NaOH solutions were investigated. Potentiodynamic polarization, electrochemical impedance spectroscopy, and galvanostatic discharge tests were used to assess the electrochemical performance of the Al-Mg-Sn-Hg-Ga anodes. The results show that the addition of 0.01 wt.% Ga in Al-0.4Mg-0.05Sn-0.03Hg anode enhances its corrosion resistance and discharge activity. It is benefited from the refined second phases and homogenous microstructure of Al-Mg-Sn-Hg-Ga anode, which restrains the local crystallographic corrosion and chunk effect. Compared with Al-Mg-Sn-Hg anode, the corrosion current density and the mass loss rate of Al-Mg-Sn-Hg-Ga anode decrease by 57% and 93%, respectively. When discharging at the current density of 20 mA/cm², the discharge voltage, current efficiency and specific capacity of the single Al-air battery with Al-0.4Mg-0.05Sn-0.03Hg-0.01Ga anode are 1.46 V, 33.1%, and 1019.2 A·h·kg^-1, respectively. The activation mechanism of Ga on Al-Mg-Sn-Hg-Ga anode materials was also discussed.