The microstructures and discharge products of Mg-6%Al-3%Zn and Mg-6%Al-3%Zn-0.5% In alloys are investigated by morphology observation, phase characterization, and composition analysis. Hydrogen collection, weight-loss measurement, and electrochemical tests are conducted to discuss their corrosion and discharge behaviors. An indium aroused dissolution-reprecipitation mechanism for Mg activation is proposed. Results suggest that the dissolution-reprecipitation mechanism can suitably interpret the indium-activation effect. Indium addition into Mg promotes Mg dissolution through synergistic effects, which involve increasing the second-phase amount, generating less-protective products, promoting products self-peeling, and dissolution-reprecipitation of indium. The homogenized Mg-Al-Zn-In alloy performs desirable corrosion resistance and discharge capability and thus is a promising candidate for applications as anode materials. (C) 2017 Published by Elsevier Ltd.