Stevia leaf (Stevia rebaudiana Bertoni) is a perennial herbaceous plant in the Asteraceae family, native to South America. Stevia contains various functional components, including glycosides, flavonoids, chlorogenic acids, alkaloids, sterols, fatty acids, polysaccharides, etc. Among them, glycosides have the most types and the highest content. The glycosides in Stevia rebaudiana are high in sweetness and low in calories. Its sweetness is about 300 times that of sucrose, but its calories are only 1/300 of that of sucrose. Human beings do not participate in metabolism, do not accumulate, have no toxicity, and have good pharmacological effects. It was recognized as an ideal flavor modifier for diabetes and hypertension patients at the Seventh International Conference on diabetes, and is internationally known as the "third sugar source", the most promising "new sugar source", and the best "natural sweetener". Stevia extract is safe, non-toxic, and has various effects and medicinal values such as antibacterial, antioxidant, anticancer, lipid-lowering, hypotensive, hypoglycemic, anti caries, anti-tumor, diuretic, etc. It has been widely used in the fields of medicine, food, beverage, health products, cosmetics, animal husbandry, aquaculture, daily chemical products, etc., with broad market prospects.