In this paper, the oxidation and combustion characteristics of Mg-Al-Gd alloy with the 2/8 mass ration of Mg/Al have been studied. The oxidation and combustion process as well as the reacted and unreacted particles of the alloy have been analyzed by using TG-DSC, SEM, XRD, EDS and high-speed camera. The results show that the ignition temperature of Mg-Al-Gd alloy in air is about 487.6 ℃, which is lower than the ignition temperature of Mg-Al alloy. Oxidation of the Mg-Al-Gd alloy in TG-DSC experiments is a staged process：The first stage is the oxidation of Mg and the second stage is the formation of MgAl2O4. When burning in air, a thin compact oxide layer will be formed firstly on the particle surface. This layer can hinder the solid or liquid phase oxidation and promote the gas phase combustion of the alloy. The combustion products of the Mg-Al-Gd alloy in air mainly contain MgO and AlN, MgAl2O4 has not been detected in the products.