Low bile duct obstruction and high bile duct obstruction both belong to bile duct and bile duct obstruction, the specific differences between them are as follows: 1. clinical manifestations: both have symptoms such as jaundice and abdominal pain, which are not easy to distinguish; 2. site of obstruction: above the opening of bile duct is high, below the opening of bile duct is low; 3. examination methods: the two cannot be obviously distinguished in liver function test, for clear distinction, MRCP examination is needed, such as high obstruction: distal bile duct without dilatation, mostly bile duct cancer in the hilar region; low obstruction: common bile duct and intrahepatic bile duct dilated throughout, mostly pancreatic head cancer, peri-pot belly cancer, duodenal papillary cancer, etc.