The electrochemical discharge behaviours of Al-0.5Mg-0.1Sn (wt%), Al-0.5Mg-0.1Sn-0.05In (wt%), Al-0.5Mg-0.1Sn-0.05Ga (wt%) and Al-0.5Mg-0.1Sn-0.05Ga-0.05In (wt%) alloys are investigated in 2 M NaCl solution. Based on electrochemical responses and microstructure observations, the influence mechanism of indium and gallium on the discharge behaviour of Al-Mg-Sn-based anode is clarified. The result indicates that Al-0.5Mg-0.1Sn-0.05Ga-0.05In (wt%) anode has the best discharge characteristics. Adding gallium accelerates active dissolution of Al-Mg-Sn anode. And adding indium leads to the appearance of discharge products (ie, In and In(OH)(3)), which inhibits the self-corrosion reaction of the anode. The peak power and peak energy density of Al-0.5Mg-0.1Sn-0.05Ga-0.05In (wt%) anodes reach approximately 92.96 mW cm(-2) (at 140 mA cm(-2)) and 3385.4 W h kg(-1) (at 20 mA cm(-2)) in 2 M NaCl solution, which increases by 447% and 104% compared with that of Al-0.5Mg-0.1Sn (wt%) anodes, respectively. Therefore, Al-Mg-Sn-Ga-In anodes could be a good and promising choice for high-speed discharge Al-air batteries in brine electrolytes.