Longitudinal wave rolling + flat roll rolling ( LFR ) is a new rolling process to reduce edge cracks and basal texture of magnesium alloy. This process can prepare magnesium alloy sheets with light edge cracks through one-pass longitudinal wave rolling + two-pass flat rolling. However, the LFR process deformation law is not clear. In this paper, the thermo-mechanical coupling finite element virtual rolling comparison and physical experiments of AZ31 plate longitudinal wave rolling + flat rolling ( LFR ) and flat rolling + flat rolling ( FFR ) were compared, the metal deformation law in the longitudinal wave rolling deformation zone and its influence on the edge damage of the plate were analyzed. The results show that a special-shaped rolling area has formed in the longitudinal wave rolling, which caused shear strain in different parts of the sheet. Furthermore, the temperature drop at the edge of the plate was avoided due to the plastic deformation heat generated by rapid metal flow, which is beneficial to improve the plasticity. The influence of shear strain and temperature promotes the formation of mixed microstructure of LFR sheet, reduces the damage of trough, and effectively inhibits the generation and development of edge crack of magnesium alloy sheet.