Abstract: The mainly nutrient content,amino acids composition and content,fatty acids composition and relative content,and parts of content of microelements in Sargassum fusiforme were studied. The results indicated that the moisture content of fresh S.fusiforme was 83.16%,the contents of carbohydrate,crude protein and crude fat in dry base were 45.77%,6.05% and 0.74%;In addition to tryptophan,16 kinds of amino acids were detected in S.fusiforme,the content of flavor amino acids was 49.73% of total amino acids,the ratio of essential amino acids to nonessential amino acids was 81.84%,and the composition ratio was consistent with the standards of high quality protein. In the 14 fatty acids contained in S.fusiforme,the contents of polyunsaturated fatty acids were 36.82% of the total fatty acids,and the content of arachidonic acid was 20.82% of the total fatty acids,rich in nutrition. The content of Pb,Cd in S.fusiforme were 4.96 mg/kg and 0.54 mg/kg,there had different degrees of excessive phenomenon. The study provided a reference for the deep processing and efficient utilization of S.fusiforme.