Abstract: Marine life is an important food source for humans, which contains a lot of high-quality protein. Marine peptides have biological functions such as anti-hypertension, anti-oxidation, and anti-tumor. They have great potential as a source of functional foods and medicines. In this paper, the related technologies of chemical hydrolysis, enzymatic hydrolysis, microbial fermentation and physical-assisted extraction to extract marine polypeptides and to separate and purify them by chromatography and membrane separation are introduced, and the differences between them are compared. The biological activities and application status of marine peptides such as angiotensin converting enzyme (ACE) inhibitory activity, antioxidant activity and anti-tumor activity were reviewed.