Abstract: Nutritional components of tilapia byproduct were analyzed and nutritive quality was evaluated.The results showed that tilapia byproduct accounted for 56.3% of the whole fish body.The contents of crude protein, crude fat, polysaccharose and crude ash of tilapia byproduct were 60.5%, 18.4%, 10.6%, 0.9% and 8.8% respectively. In dry sample, the total content of amino acids was 26.38%, among which essential amino acids and delicious amino acids accounted for 36% and 45%.The ratio of essential amino acids to non-essential amino acids was 55%.The amino acids index ( EAAI) and the biological valence ( BV) were 83.16 and 78.95 respectively.The constitutional rate of the essential amino acids accorded with the FAO/WHO Standard.The unsaturated fatty acids accounted for 50.8% of the total fatty acids.Calcium ( Ca) was the most predominant mineral element and its content was 43600 mg/kg. In conclusion, tilapia byproduct is a valuable marine biology resource rich in protein, fatty acids and mineral elements, which should be fully utilized.