Primary sclerosing cholangitis (PSC), also known as stricture or obliterative cholangitis, is a rare bile duct disease of unknown cause and slow course. It is characterized by extensive fibrosis of the intrahepatic and extrahepatic bile ducts, with significant thickening of the duct wall and significant narrowing of the duct lumen. In addition to obstructive jaundice, if the patient fails to receive timely diagnosis and treatment, it may eventually lead to biliary cirrhosis and portal hypertension, and death from liver failure and upper gastrointestinal bleeding. The age of onset is mostly between 30 and 50 years old, and there are more males than females. At present, bacterial and viral infections, abnormal immune function and certain congenital genetic factors are believed to be possible causes of this disease.