Abstract: In this paper, high purity magnesium(purity:99.95%)was chosen as research object.The commercial software DEFORM was utilized to simulate the deformation process of M-ECAP.The flow of material, forming load, equivalent stress and strain and the effect of friction on the M-ECAP deformation process were investigated. The results show that sample tends to be more uniform and equivalent strain accumulated variables should be increased, grain fine and homogeneous. The plastic is improved effectively. Load increases gradually with the increase of friction factor, while the maximum equivalent strain change is not obvious and the maximum equivalent stress decreases.