Biliary obstruction is a mechanical obstruction of the bile duct caused by lesions in the bile drainage tract, resulting in poor bile excretion or even complete blockage, with the following common causes: 1. tumor diseases: such as bile duct cancer and pancreatic head cancer, which are more harmful and commonly manifest as progressive aggravation of painless jaundice; 2. inflammatory diseases: such as cholangitis, inflammatory stricture, and inflammatory stricture of duodenal papilla; 3. stone diseases: such as bile duct stones, which can cause biliary obstruction; 4. congenital diseases: such as congenital bile duct stricture and congenital bile duct dilatation, etc.