Provided is a novel method for preparation and processing of a high-performance magnesium alloy profile. According to the method, magnesium alloy materials of the same type are subjected to plastic processing through the different-temperature hot extrusion technology, or a magnesium alloy material and a dissimilar alloy material are subjected to plastic processing through the identical-temperature/different-temperature hot extrusion technology, the extrusion speeds and the deformation speeds in the direction perpendicular to the axial direction are different due to the different temperatures or material types, then shear strain is generated on a contact interface, a basal texture weakening effect is achieved for magnesium alloy plates formed through hot extrusion, and the forming property is improved; and a grain refinement effect is achieved for magnesium alloy bars formed through hot extrusion, and the strength of the magnesium alloy bars is improved.