By means of the analysis of the species and ingredient and biological characteristics of the alfalfa shows that:there are a mass of valuable nutrition and functional ingredient in the alfalfa in use, for example, alfalfa protein, active polysaccharide, mineral etc. The extraction of the alfalfa nutrient and the possibility and the problems need to be solved when applied in functional food are analyzed. The conclusion shows that after suitably extracted the nutrition ingredient of the alfalfa will have a wider applied prospect in function food.