The MB2 magnesium alloy profile bar with high strength and plasticity which was modified by Re and some special elements was prepared by extruded forming at 330 ℃.Effects of modification elements on microstructure and properties of the Mg alloy profile bar before and after deformation was observed by optical microscope（OM）

image analysis system and MTS-810 materials testing system.The results reveal that the morphology of β-Mg17Al12 phase is converted from the continuous net-like structure into dispersive particles and the grain size is decreased from 100

2

00 μm to 15

3

5 μm in the modified magnesium alloy.The grain size of the modified MB2 magnesium alloy after deformation is further refined to 5

1

0 μm

and tensile strength and elongation are remarkably increased from 247 MPa and 13% to 312 MPa and 22%

respectively.