Abstract: In this study, the polypeptide of Anser cygnoides blood was extracted by enzyme hydrolysis and the effect of extraction process on the degree of hydrolysis was investigated.Using fresh Anser cygnoides blood as raw material, the extraction process was optimized by single factor tests and response surface experiment.And the molecular weight distribution was determine by SDS-PAGE electrophoresis. At the same time, mouse spleen lymphocyte proliferation assay was used in this work. The polypeptide from Anser cygnoides blood was separated and purified by ultrafiltration and gel filtration chromatography. The contents of cytokines IL-2, IFN-γ and PGE2 were detected by ELISA. The results showed that the optimum extraction conditions were as follows:The hydrolysis temperature was 47℃, the pH was 7, the amount of enzyme was 4500 U/g and the hydrolysis degree was 29.29%. The enzyme hydrolysis effect of complex protease was the best. The proliferation of lymphocytes could be promoted at different concentrations before and after the hydrolysis of Anser cygnoides blood protein. Three component peptides were isolated and purified from the peptides of Anser cygnoides blood. ACP1, ACP2 and ACP3 could promote the secretion of IL-2 and IFN-γ by mouse lymphocytes and inhibit the secretion of PGE2.The effect of ACP2 was the best at the concentration of 100 μg/mL.Thus, it could be determined that the Anser cygnoides blood protein polypeptide had a certain immunomodulatory effect. It would provide a theoretical basis for the deep development of immune mechanism of Anser cygnoides blood protein peptide.