Tetrastichopus unicinctus, commonly known as sea intestine and sea intestine, belongs to the genus Tetrastichopus, Tetrastichopus, Acanthopoda, Tetrastichopus. It is a long cylindrical annelid, crawling limply, with no burr and light yellow. Sea sausage not only looks like a sea cucumber without thorns, but also has the same nutritional value as sea cucumber. Distributed in Russia, Japan, Korea and Bohai Bay in China, it is a common species of benthos in the northern coastal areas and shallow waters of China.