Fucoidan is a water-soluble sulfated heteropolysaccharide, a pure natural polysaccharide of marine uniquely derived from brown algae such as kelp. This article summarized the physicochemical properties of fucoidan such as the source, extraction, chemical structure. And its effects on immune regulation, anti-tumor, anti-oxidation, anti-coagulation and thrombosis, hypolipidemic, anti-bacterial, anti-viral, anti-arthritis, prevention gastric ulcer, neuroprotection, regulation of fat metabolism, alleviation of diabetic complications, regulation of bone metabolism, protective effect of the intestinal barrier function, promotion of wound healing, anti-aging and other functional characteristics were elucidated. The research progress and application of fucoidan in foods in Japan, the United States, South Korea, China and other countries were elaborated, which had great value for the further development of fucoidan in the health industry.