Abstract: Algal polyphenols,a class of secondary metabolites existed in algae,have multiple biological activities due to their unique chemical structure,and are becoming a hot research direction of marine bioactive substances.In this paper,the biological activities of algae polyphenols were described,such as antibacterial,antioxidative,antitumor,anti-obesity,anti-diabetic,anti-radiate,anti-allergic,antiasthmatic and antiviral activities.The research progress on their modification with metal ion,protein,polysaccharide and other substances was simply introduced.The application foreground of algae polyphenols in food preservation,functional food development and cosmetics industries was also predicted.