Abstract: AZ31 alloy was cold rolled under different rolling angles and subsequently annealed to refine the grain size.The effects of deformation conditions on the plasticity were investigated through tensile tests under different temperatures,strain rates and grain sizes.Meanwhile,superplastic deformation mechanism was investigated.The results show that the flow stresses were decreased and the elongations were increased with the temperature increase.In the temperature range of 150-300 ℃,the deformation activation energy was 90 kJ·mol-1,the deformation mechanism was dislocation creep controlled by grain boundary diffusion.In the temperature range of 300-350 ℃,the deformation activation energy was 123 kJ·mol-1,the deformation mechanism was grain boundary slip controlled by lattice diffusion.The plastic deformation conditions of the alloy were suitable for industrialized production.