Abstract: The present study analyzed and evaluated the nutrient components in Ostrea rivularis from south China sea coast,and discussed the effect of visceral mass on the nutrient components.The results showed that the contents of water,crude protein,fat and ash in the Ostrea rivularis were 84.90%,7.64%,0.75% and 1.71%,respectively.Sixteen amino acids were found which contained seven essential amino acids in the range of 3.97 g/100 g to 7.60 g/100 g,the ratio of EAA/TAA was in range of 33.86% to 38.06%.Among of them,methionine acted the first limited amino acid,and flavour amino acids accounted for 38.42% to 43.25% of the total amount of amino acid,there were rich trace elements in Ostrea rivularis,such as Ca,Fe,Zn,and Se.The content of fat in eviscerated Ostrea rivularis was lower than that of the whole,while the protein content was higher than that of the whole Ostrea rivularis.The total amino acid content showed slight increasing to 5.83 g/100 g.Essential amino acid in eviscerated Ostrea rivularis was accounted for 35.59% of total amino acid,while flavour amino acid accounted for 41.16%.The content of mineral elements were similar to the whole Ostrea rivularis,and the content of zinc increased.Therefore,Ostrea rivularis was a kind of aquatic product with good quality and high nutritional value,and the nutritional value was increased slightly in eviscerated Ostrea rivularis.It was of great significance to protect the safety of consumer that remove oyster visceral mass to eat.