Abstract: The low room-temperature plasticity and deformability of magnesium alloys restrict their engineering applications. A deep understanding of their plastic deformation mechanisms, and clarifying the plasticity-enhancing effects of alloying,thermomechanical processing and heat treatment form the foundation for achieving plasticity regulation in magnesium alloys.The plastic deformation mechanisms of magnesium alloys were first introduced, and it is pointed out that the fundamental reason for their poor room-temperature plasticity is the insufficient number of activatable slip systems to meet the Von Mises criterion. Existing plasticity regulation strategies for magnesium alloys can generally be classified into intrinsic plasticity and extrinsic plasticity. Intrinsic plasticity regulation strategies primarily include reducing the critical resolved shear stress ratio between non-basal and basal dislocations and lowering the stacking fault energy to activate non-basal slip systems. Extrinsic plasticity regulation strategies involve controlling grain size, precipitates, texture, and elemental grain boundary segregation,that is promoting the activation of multiple slip systems through the regulation of microstructural features.