In order to evaluate the nutritional value of Ascophyllum nodosum, the contents of main nutrients, such as amino acids, fatty acids, inorganic elements, heavy metals, alginate and mannitol were analyzed. The results showed that the main component of Ascophyllum nodosum was total dietary fiber, which accounted for 40.68% of its dry weight. The content of soluble dietary fiber was 8.54%.The content of crude protein was 9.66% and 18 kinds of amino acids were detected. The total content of amino acids was 7.99 g/100 g, among which the essential amino acids accounted for 37.90% and taste amino acids 40.25% of total amino acids, respectively. The first limiting amino acid was threonine and the amino acid score was 134.98, which indicated that the proportion of amino acids was balanced. The content of crude fat was 1.53%, in which the content of unsaturated fatty acids accounted for 43.92% of the total fatty acids. The ash content was 39.43% with rich macroelements K, Na, Ca and microelements Fe, Zn and Sn. The alginate and mannitol content were high. In conclusion, Ascophyllum nodosum is a kind of algae with high dietary fiber, high protein, and low fat, indicating that it has high development and utilization value in the fields of food, seaweed chemical industry and feed.