Nutrient components in the muscle of Siganus oramin were investigated in this paper. Sample fish(n=10) were collected from t he South China Sea, near Qionghai city of Hainan Province in May of 2006. The ex amination results showed that the content of moisture, crude ash, crude protein and crude fat in fresh muscle of S. oramin were 74.52%, 1.09%, 19.64 % and 4.71%， respectively. Eighteen common amino acids were found in the muscle of S. oramin, including 8 essential amino acids(EAA), 2 halfessential amino acids (HEAA) and 8 nonesse ntial amino acids (NEAA). In dry sample, the total content of amino acids(TAA) was 68.33%; the content of EAA，HEAA and NEAA were 30.40 %，6.40% and 31.55% respectively. Four kinds of delicious amino acids(DAA) accounted for 24.37% in dry sample; the ratio of total delicious amino acids to total amino acids (WDAA/WTAA) was 35.66%. The essential amino acids index(EAAI) was 61.07, the ratio of total essential amino acids to total amino acids (WEAA/WTAA) was 44.48%, and the ratio of total essential amino acids to total nonessential amino acids(WEAA/WNEAA) was 96.35%. It was clear that the content of the different ami no acids was stable and the constitutional rate of the essential amino acids met the Food and Agriculture Organization of the United Nations/World Health Organ ization (FAO/WHO) Standard. According to nutrition evaluation in amino acids sco re (AAS) and chemical score (CS), the first limited amino acid w as Met + Cys and the second limited amino acid was Trp. 10 saturated fatty acids (SFA), 6 monounsaturated fatty acids (MUFA) and 9 poly unsaturated fatty acid s (PUFA) were found in the muscle of S. oramin. The contents of EPA and DHA in fatty acids were 3.13% and 18.03%， respectively, which were much higher tha n those of most fish species. The composition of mine ral elements in the muscle of S. oramin was reasonable and the t race elements such as Zn and Se were rich. In conclusion, this investigation ind icated that S. oramin is a nutritive and delicious food fish, an d it could be a potential aquaculture species.