Abstract: This article focused on the typical processing by-products of sea cucumber (A.japonicus), including intestines and ovum, to explore their nutritional composition and conduct a comprehensive evaluation by comparing them with body walls. The results showed that the crude protein, crude fat, ash, and total sugar contents in sea cucumber intestines and ovum were 68.85%, 13.53%, 9.96%, 0%,and 58.18%, 12.24%, 19.01%, 2.36%, respectively. In comparison to the body walls, the by-products exhibited higher crude protein and fat contents, but lower ash and total sugar contents. The intestines and ovum were found to contain 18 different amino acids, constituting 68.15% and 51.38% of the total amount, respectively. The ratio of essential to non-essential amino acids was 65.17% and 61.37%, respectively, with essential amino acids accounting for 39.46% and 38.03% of the total amino acids. The essential amino acid index was 94.85 and 67.73, respectively, suggesting that both the intestines and ovum possessed high nutritional value as they exhibited a good balance effect of amino acid components, identifying them as ideal protein sources. The unsaturated fatty acids constituted a similar proportion of total fatty acids, with 80.82% and 80.74%, respectively. Notably, EPA and DHA were the major components of these fatty acids. Additionally, five macro elements and five trace elements were detected, with sodium and iron being the primary elements. This study serves as a foundation for the high-value utilization of sea cucumber by-products and the development of active substances.