Sericin is refined from silkworm body (spun silk gland), pod (pod shell,watt silk) and silk. There are 18 kinds of amino acids in sericin, among which, serine and aspartate have the highest content. Besides, it has the other amino acids necessary to human body, so it is an excellent protein. Because in sericin, about 80% amino acid has hydrophilic lateral group, about 1/3 of which is sericin whose water absorption is increased by 50 times compared with glycerin. Sericin, as the raw material of cosmetic, has excellent moisture absorption and preservative ability. Sericin protein can form a film on the surface of skin and hair so that the water in skin can be preserved, and then the harm to skin cutin can be avoided. By applying it, the skin can be soft and smooth, and the hair can be soft and flexible, and it also benefits for the shaping of hair. Meanwhile, it will not adhere to hair.