Abstract: Alfalfa, a genus of the genus Eucalyptus, is rich in minerals, protein and vitamins. These characteristics make it an ideal choice tor livestock teed, and because of its high grass yield, long lite, and regeneration. It has the advantages of strong sex and strong palatability, and is known as the ＂king of the pasture＂. In addition, alfalfa contains a variety of active ingredients, including： minerals, amino acids, non-protein amino acids, organic acids, polyols, alkaloids, carotene, coumarin, digestive enzymes, flavonoids, phenolic compounds, plants Estrogen, phytosterols, polyamines, saponins and other volatile organic compounds such as terpenes, turans, alcohols and ketones. In this paper, the functions of the active constituents of altalfa and their analytical methods were reviewed. The active constituents of altalfa were divided into three types： minerals, primary metabolites and secondary metabolites. The types of specific compounds, the physiological functions of the active ingredients, and the related analytical techniques, and the ettective analysis methods for various active compound components in altalth, aim to provide an advantageous technical reterence tor scientific research in future alfalfa active substances.