Abstract: Four kinds of Mg-15Gd-0.2X (X=Mn,Ni,Zn,Sn)alloys with different microalloying elements were prepared by semicontinuous casting method. OM,SEM and XRD were used to observe the microstructure of the alloys,analyze the microstructure of the alloys,and test the corrosion resistance of the alloys by immersion corrosion and hydrogen evolution experiments. The effects of different microalloying elements on microstructures and corrosion resistance of Mg-15Gd alloy were studied. The results show that the addition of microalloying elements obviously improves the as-cast microstructure,refines the grain and the second phase,and makes the second phase Mg₅Gd distribute in a network along the grain boundary.The corrosion resistance of all the alloys except Mg-15Gd-0.2Ni alloy is improved significantly after the addition of microalloying elements,which is mainly related to the grain refinement,the second phase refinement and the network distribution along the grain boundary,the blocking effect on the corrosion of the alloy,and the complete and compact alloy corrosion product film with good protection.