Selenium is one of essential trace elements for animal production. Its most important role of nutritional physiology involved the composition of glutathione peroxide to eliminate free radicals, and has an important relationship with semen quality in male animals. Selenium, by influencing the secretion of male hormone, was involved in the composition of sperm and antioxidant enzymes, and the occurrence and maturation process of sperm, which ultimately affected semen quality. Production of selenium in the rational application of boar can significantly improve production performance. Selenium level of 0.3 mg/kg in the diet is conducive to the improvement of semen quality.［Chinese Journal of Animal Nutrition, 2010，22（6）:1488-1494］