Abstract: The nutritional components and quality of muscles from Epinehelus moara, E. lanceolatus and hybrid " Yunlong grouper” were investigated and evaluated to provide basic data for the nutritional evaluation of their germplasms and the development of compound feed. The composition and content of water, protein, crude fat, ash content, amino acids, fatty acids and 10 mineral elements in the muscles of three groupers were measured by conventional methods, according to the national standard. The crude protein contents in the muscles of E. moara, E. lanceolatus and " Yunlong grouper” were 19.6%, 18.4% and 19.4% respectively. The total quantity of amino acids, essential amino acids, essential amino acid index and the flavour amino acids of these three groupers were (15.54%, 14.72%, 15.99%), (6.86%, 6.41%, 7.04%), (75.19, 74.93, 77.96) and (5.57%, 5.3% and 5.73%) respectively. The fat content in the muscle of three grouper is 4.2%, 10.1% and 4.5% respectively; the fat are rich in fatty acids variety and polyunsaturated fatty acids, and the ratio of polyunsaturated fatty acids/total fatty acids is consistent with ideal fatty acids. There are abundant mineral elements in the muscles of three groupers; five major elements (K, Ca, Na, Mg and P) and five kinds of trace elements (Fe, Mn, Cu, Zn and Se) have been detected. Among them, the contents of Na, K and Cu in hybrid " Yunlong grouper” are slightly higher, and the contents of other kinds of mineral elements are among parents. The research shows that E. moara, E. lanceolatus and " Yunlong grouper" contain all kinds of amino acids, suitable ratios of essential amino acids, a lot of unsaturated fatty acids and abundant mineral elements. Thus, the three groupers are excellent seawater breeding varieties with high edible value. In addition, " Yunlong grouper” shows some superiority in some nutritional indicators compared with their parents.