Abstract: Magnesium alloy is a kind of light metallic material, which excels in high specific strength and specific stiffness, good damping property, good properties in electromagnetic screening, and anti-irradiation performance, so it is widely used in spacecrafts. This paper analyzes the bottlenecks in processing magnesium alloy, such as the corrosion resistance, the welding, the machining and shaping. The problems and risks of the magnesium alloy applications in spacecrafts at different conditions are discussed, together with related process methods and proposals.