A portal vein internal diameter of 18 mm is more serious. The normal internal diameter of the portal vein is 8 to 10 millimeters, and if the internal diameter of the portal vein is 18 millimeters, it is a manifestation of portal vein dilatation, suggesting portal hypertension. When the blood flow in the portal vein system is obstructed, causing the portal vein pressure to rise, splenomegaly, esophagogastric fundus varices and other manifestations are often seen in clinical practice, which are more serious and may be life-threatening. Portal hypertension is most common in the decompensated stage of liver cirrhosis in China, patients should go to the hospital in time, improve the abdominal ultrasound, abdominal CT, blood biochemistry, gastroscopy and other related auxiliary examinations, to clarify the cause of portal hypertension, take appropriate treatment, and if necessary, surgical treatment. The internal diameter of portal vein is 18mm, it is recommended that the patient should consult the regular hospital as soon as possible to clarify the cause of the disease.