Abstract: Nutritional composition and quality evaluation of Ryukyu squid in South China sea was analyzed by using the modern biochemical analysis. The results showed that the water, fat, protein and ash in the carcass of Ryukyu squid were 80.50%, 0.49%, 17.24% and 1.37%, respectively. The levels of moisture, fat, crude protein and ash in the head and foot of Ryukyu squid were 80.73%, 0.87%, 16.68% and 2.88%, respectively, which indicated that the Ryukyu squid in South China sea had a high protein and low fat seafood. The amino acids were very rich in Ryukyu squid, in wet samples, the content of total amino acids in the carcass and head and foot of Ryukyu squid was 14.05% and 15.10% respectively. Necessary amino acid was about 40.89% and46.51% of total amino acid in the carcass and in the Head and foot of Ryukyu squid. The essential amino index (EAAI) was 79.56 in the carcass and 75.46 in the head and foot, the proportion of essential amino acids constitute compliance FAO/WHO standards. The PUFAs in the carcass and head and foot of Ryukyu squid accounted for 49.90% and 54.55% of total fatty acids, respectively. The contents of EPA and DHA were 6.9%and 15.26% in the carcass, 5.67% and 22.08% in the head and foot. These results indicated that Ryukyu squid in South China sea possess had high nutritional value and health care function, it had promising prospects for further development.