The normal diameter of portal vein is 1.5 cm, and exceeding this value is called portal vein widening. Portal vein widening is mostly caused by liver diseases, such as hepatitis, cirrhosis, liver cancer, fatty liver, intrahepatic bile duct stones, hepatic hemangioma, liver cyst, etc. Portal vein widening can be caused by a variety of causes of portal hypertension. Once the symptoms of portal vein widening appear, go to the gastroenterology department of regular hospital for examination as soon as possible to find out the cause of portal vein widening and take corresponding treatment plan according to the cause to avoid delaying the disease, otherwise the disease will be easily aggravated and sometimes even life-threatening. It is important to ensure a light, nutritious and easily digestible diet, and to quit smoking and drinking.