Adults are oval and thick, fresh worms are flesh red, with flat back and abdomen, narrow front and wide back, 20-75mm long, 8-20mm wide and 0.5-3mm thick, with spines on the body surface, making them the largest trematode in human body. The mouth sucker is close to the front of the body, with a diameter of about 0.5mm, and the abdominal sucker is close to the back of the mouth sucker, which is funnel-shaped and muscular, 4-5 times larger than the mouth sucker and can be seen by the naked eye. The pharynx and esophagus are short, and the intestinal branches are wavy and extend backward to the end of the worm; Two testes, highly branched, are arranged in the back half of the worm. The penis bag is long and baggy. The ovary has branches. The uterus is coiled between the ovary and the abdominal sucker. Lack of seminal vesicle, Lloyd's tube. The yolk glands are well developed and distributed on both sides of the worm. The genital foramen is located at the front edge of the abdominal sucker. The egg is oval with the size of130-140 & micro; m×80-85& micro; M, light yellow, with thin egg shell and an inconspicuous egg cover at one end. An egg contains one egg cell and about 20-40 yolk cells.