Abstract: The asymmetric cross rolling process was developed and applied to roll the alloy using AZ31 magnesium alloy as research object.The effects of velocity ratio of upper and lower rolls,total pass number,rolling route and rolling temperature on the microstructure and mechanical properties of the alloy were investigated.It is found that the shear strain of asymmetric cross rolling with different velocity ratios of upper and lower rolls contributed to refinement of grain size.With the increase of rolling temperature,the grain size increased gradually,strength increased and elongation reduced.Fewer passes were benificial to the microstructure and properties under the same total soft reduction amount.The rolling route had some effect on microstructure and properties.