The invention relates to the field of 
yeast polypeptides, in particular to a 
yeast polypeptide and its preparation method and application.  The preparation method of the 
yeast polypeptide comprises the following steps: (1) extracting the yeast 
protein in the 
raw material; (2) adding 
alkaline protease for enzymolysis, then adding compound 
protease for enzymolysis, collecting the supernatant to obtain the enzymolysis product; (3)  ) separation and decolorization to obtain yeast polypeptide.  The yeast polypeptide obtained by the present invention is colorless and tasteless, with a polypeptide content of more than 80%, and more than 85% of the polypeptide has a molecular weight of less than 2000, contains almost no 
free amino acids, and does not have the 
bitter taste of general soybean 
peptide and other 
peptide products, and can be used in food  And health care products, which can improve the 
flavor of food, help restore 
physical strength after exercise, etc.  Moreover, if the yeast polypeptide obtained in the present invention is not dried and powdered, it is an excellent cosmetic essence, which has nourishing and anti-
wrinkle activity, can be applied to 
cosmetics, and does not affect the color, fragrance, etc. of 
cosmetics, and has anti-aging effects  .