To determine the nutritional composition of sea urchin gonad and systematically analyze and reasonably evaluate its national value, the national standard biochemical assay method and Association of Official Analytical Chemists (AOAC) method were used to determine the moisture, crude ash, crude protein, crude fat, total sugar, amino acid, fatty acid, and minerals in sea urchin gonad. The results showed that, the moisture content was (5.29±0.02)%, crude ash (8.69±0.03)%, crude protein (51.31±0.09)%, crude fat (25.32±0.09)% and carbohydrate (0.044±0.002) mg/100g; 18 kinds of amino acids were detected with a total content of (46.50±0.89)%, the most predominant amino acid was glutamic acid, being (5.57±0.11)%, and the essential amino acids accounted for (37.75±0.01)% of the total amino acids. The main limiting amino acids were tryptophan and leucine, and medicinal qualities of amino acids accounted for 46.86% of the total amino acids. The evaluation scores were AAS>0.8, CS>0.5, and the essential amino acid index EAAI was 77.86. Thirty kinds of fatty acids were found in sea urchin gonad, the content of EPA and DHA was (2.43±0.05)%; it was rich with mineral elements such as K, P, Na, Mg, Fe, Zn, etc.. Among the major elements P was the highest in content with (1 432.27±8.91)mg/100g and Zn was the highest in the major trace elements being (13.13±0.09)mg/100g. The research indicates that sea urchin gonad is rich in protein, with many kinds of amino acids in reasonable proportion, high content of EPA and DHA as well as rich minerals.