The hepatic portal vein is composed of the splenic vein, inferior mesenteric vein, superior mesenteric vein and gastroduodenal vein. 1. Splenic vein, inferior mesenteric vein: the main function of the splenic vein, inferior mesenteric vein is to collect blood from the spleen vein and the inferior mesenteric vein, and it can join with the superior mesenteric vein to form the hepatic portal vein. 2. Superior mesenteric vein: The role of the superior mesenteric vein is to collect blood from the large and small intestine and to join the splenic vein near the pancreas to form the hepatic portal vein. 3. Gastroduodenal vein: The gastroduodenal vein is mainly responsible for combining the food transferred from the stomach with digestive enzymes such as bile and pancreatic juices, in order to promote absorption and deliver the food to the jejunum. The invasion of the hepatic portal vein system is also a major factor affecting the prognosis of the disease, so it is recommended that when discomfort occurs, timely medical examination, under the guidance of the doctor to carry out appropriate treatment.