The microstructure and corrosion properties of AZ31 alloy with microalloying Ca and Ce addition were studied. The microstructure was examined by SEM, EBSD and EDS. The corrosion behavior was evaluated by immersion tests and electrochemical tests. The microalloyed alloys had much finer grains than the AZ31 alloy. The AZ31 alloy possessed a small quantity of coarse Al8Mn5 phase particles. In contrast, the microalloyed alloys possessed a relatively higher number of the smaller second phase particles: Al2Ca, Al(11)Ce3 and Al8CeMn4 besides Al8Mn5. The corrosion rates ranked as AZ31-0.2Ca < AZ31-0.2Ca-0.2Ce < AZ31-0.2Ce < AZ31. The Ca micro-alloying was more effective in decreasing the corrosion rate than Ce, attributed to the Ce-containing second phase causing more severe galvanic corrosion with the alpha-Mg matrix than the second phase containing Ca, and that Ca was in the corrosion products, which could improve the protectiveness of the corrosion products film. (C) 2019 The Electrochemical Society.