The effects of revolving magnetic field on the microstructure, mechanical properties and corrosion resistance of the AZ91D-0.4%RE alloy were investigated. It is found that under the revolving magnetic field, the grain size of α-Mg dendrite was obviously decreased and became more uniform with the increasing of excitation voltage; the additional phases of Al11RE3 became smaller and changed from fishbone or long-acicular structure to short acicular structure gradually. Under the revolving magnetic field, σb, σ0.2, δ and hardness of the alloy can be increased by 13%, 15%, 44% and 19%, respectively. The room-temperature tensile fracture shows a feature of quasicleavage fracture. Meanwhile, the self-corrosion potential increased from –1.56 V to –1.51 V, indicating that the corrosion resistance was greatly enhanced.