Daylily is rich in various nutrients and bioactive substances， and is known as one of the four treasures among vegetables along with shiitake mushrooms， fungus， and winter bamboo shoots. This article reviews the biological activity of daylily and the current research status of its deep processing technology. It explores the relationship between the bioactive components and functions of daylily extracts， and further analyzes that the weak links in the value-added processing of daylily mainly lie in the development of daylily extracts as new food raw materials and the study of their toxicity. Summarizing the potential applications of daylily and its extracts in antioxidant， antidepressant， anti-tumor， anti-inflammatory and other related diseases， and elaborating on the application of daylily deep products such as daylily powder， daylily beverage， ready to eat products， daylily extracts， etc. It is proposed that daylily and its extracts can be used as new food raw materials in the future， providing some reference for the development of daylily functional products.