Abstract: In order to make better use and implement more applications in functional foods of notoginseng flower. We researched the immune regulating function in this paper.Notoginseng flower extract was prepared by water extract method and freeze drying.The effection on the NK cell activity in mice was researched by Lactate dehydrogenase (LDH) method. Then we can realize the immunomodulation function of notoginseng flower. The result indicates that the extract contain 75.48% soluble polysaccharide and 5.35% total saponins. The extract could significantly enhance the activity of NK cells in mice within the limits of consistency 62.5~1 000 μg/mL. As soon as the concentration is above 250 μg/mL, the promotive effect would be more significant. The results show that notoginseng flower extract has potential immunomodulatory function, and could be widely used to develop functional food.