Nutrition and solubility were evaluated by assaying amino acids composition, AAS, EAAI, NSI and TCA-NSI of hydrolysate from Urechis unicinctus body wall muscle. The results showed that there were all of 18 types of amino acids, and umami amino acids were rich. In umami amino acids, the highest was Glu, 218.263 mg/100 mL, followed by Gly and Ala, third for Asp. Hydrolysate had strong delicious taste and it was a good seafood seasoning base. AAS of EAA was at range of 96～141, and EAAI was 86.50. They showed that EAA was rich and hydrolysate had a high nutritional value. When pH was at the range of 4.5 to 8.0, nitrogen solubility index (NSI) was over 97%. Especially, when pH was 7.0, NSI reached the highest value 99.65% and TCA-NSI also reached 99.60%. Hydrolysate had a high solubility.