L-citrulline has many important physiological functions, such as scavenging free radicals, allogeneic rejection effect indicator, vasodilation, stabilizing blood pressure, diagnosing rheumatoid arthritis, antioxidation, etc; In addition, it has a very significant recovery of energy and improve the human immunity. In recent years, L-citrulline has been paid more and more attention in food, cosmetics and drugs, and has a wide development and application prospect.