A new severe plastic deformation (SPD) K has been explored which includes two consecutive processes, i.e. initial forward extrusion and subsequent shearing process. The process can be shortened as Extrusion-Shearing (ES). The geometrical and numerical models for the structures of ES forming die have been built. Initial and boundary conditions were exerted and FEM molding has been simulated. The structures of ES forming die have been manufactured and installed to Gleeble1500D thermo-mechanical simulator. Physical modeling of ES forming has been done by instituted procedures. Microstructure observations have been carried out on the extruded rods (as-received) and ES formed rod from simulator. From the research results, the ES forming can produce the severe plastic deformation and improve the volume fraction of dynamic recrystallization. The ES simple shear process can produce intense deformation by the combination of forward extrusion and provides a convenient procedure for introducing an ultra fine grain size into a material. The results show that the ES forming process affected both the microstructure of AZ31 Mg alloy. These results can be explained by the effects of the process on microstructure of AZ31 Mg alloy such as grain size and dislocation density caused by the change in recrystallization behavior