Primary sclerosing cholangitis is a chronic bilious disease of unknown origin. It is characterized by diffuse inflammatory stenosis of the intra- and extrahepatic bile ducts, causing bile duct occlusion and biliary cirrhosis. The pathogenesis is mainly autoimmune abnormalities. The cause may be related to genetics, viral infections, bacterial toxins, etc. The pathological changes are inflammatory cell infiltration, fibroplasia, scar formation, duct wall thickening with segmental distribution and alternating stenosis and dilatation. The diagnosis mainly relies on MRCP, ERCP. differential diagnosis: biliary duct disease of AIDs, biliary tumors, biliary surgery trauma, common bile duct stones, congenital bile duct anomalies, erosive sclerosing cholangitis, ischemic bile duct stenosis, secondary biliary inflammatory stenosis caused by arterial perfusion of fluoxuridine. For treatment, ursodeoxycholic acid, fat-soluble vitamins, and digestive enzymes can be applied. Diet should reduce cholesterol and fatty acid intake, supply medium-chain triglycerides, linoleate, and increase sugar and protein content, which can be with elemental diet in late stage. Application of immunosuppressants can also be considered.