Superoxide dismutase (SOD) is a category of metalloenzyme, extensively existing in all living organisms (e.g. animals, plants, microorganisms, etc.). Based on its metallicity, SOD is categorized into copper, zinc-SOD (Cu, Zn-SOD), manganese-SOD (Mn-SOD) and iron-SOD (Fe-SOD). SOD has a physiological significance that can convert toxic superoxide free radicals into hydrogen peroxide, it’s the primary substance to scavenge oxygen free radicals in living organisms. It has been demonstrated that there are up to 60 diseases directly related to oxygen free radicals and SOD level has been known as an illustrated indicator for aging and death. SOD can prohibit superoxide free radicals-induced damage at cellular level and locally repair damaged cells. It plays more and more important role in anti-oxidation in living organisms. SOD is one of components in cosmetic products, approved by Ministry of Health of the People’s Republic of China, because it can delay aging, regulate immune response and blood lipid level, and prevent radiation.