Abstract: As one of high quality legumes, alfalfa is becoming more and more important. Alfalfa contains many biological active components, which also have medicinal value and feeding value, such as saponin, leaf protein, flavonoid, polysaccharide, natural pigment and dietary fiber. In which, alfalfa saponin, with the functions of reducing cholesterol level, antioxidization, immune improvement, could enhance the growth performance of livestock and poultry. The structure, physical and chemical characters, biological functions, extraction techniques of alfalfa saponin and its application in animal production were discussed, and the current situation and development prospect were analyzed as well.