Abstract: The requirement of complex structural parts were increaced which had the demand of lightweight and high mechanical performance, the traditional manufacturing process and materials were not satisfied the technical requirements of the products. Magnesium alloy was satisfied the technical requirements which was manufactured by isothermal and multiple forging process. This paper was analyzed the forging process and made the performance improvement experiment for magnesium alloy. After multiple isothermal forging for magnesium alloy, the microstructure of magnesium alloy was optimized, and the grain distribution was adjusted more uniform, the tensile strength was increased 20%, and the elongation was increased 113%. At the same time, multiple isothermal forging could repaired the defects of the first forging by the action of thermal machinery, which improved the density of the material, eliminated the internal stress during the first forging process, improved the stability and service life of the material. The magnesium alloy will be applied in the mass production of aerospace, biomedical, motor parts and lightweight parts.