Abstract: With the development of economy,people have higher and higher demand for nutrition,and pay more attention to the pursuit of higher quality protein. The whey protein hydrolysate obtained after hydrolysis of whey protein has been widely used and has become a research hotspot in recent years,due to its easy absorption,high protein quality and many biologically active peptides. Therefore,the preparation method of whey protein hydrolysate,its biological activity and its application in food were discussed in this article,and its future development was prospected to facilitate the further development and utilization of whey protein hydrolysates.