Portal vein internal diameter of 10mm is normal. Portal vein is an important blood vessel for the return of gastric and intestinal veins to the liver. Gastric vein, small intestinal vein, colonic vein, etc. first converge to form superior mesenteric vein, inferior mesenteric vein, and then finally converge into portal vein, and then return to the liver, so the portal vein is an important channel for absorbing nutrients from the digestive tract. The portal vein is generally about 8cm long, and the inner diameter of the main trunk is 6~10mm, up to 15mm, so the inner diameter of the portal vein of 10mm is normal. In addition, breathing will affect the diaphragm compression of the liver, resulting in the obstruction of blood flow in the liver, resulting in changes in the internal diameter of the portal vein, so changes in the internal diameter of the portal vein, is a normal phenomenon. If physiological influences are excluded and the portal vein internal diameter is larger than normal, then we should actively consult the doctor to clarify the cause of portal vein widening and target treatment.