The intrahepatic bile ducts are located in the human liver and are usually of different thicknesses. Generally, the intrahepatic bile ducts start from the capillary bile ducts, which are relatively thin bile ducts, and then gradually merge into the bile ducts of the hepatic segments and lobes, as well as the left and right hepatic ducts of the intrahepatic part. The classification of intrahepatic bile ducts is usually divided into three levels: primary branches, secondary branches and tertiary branches. Primary branches refer to the thicker bile ducts, which are the left and right hepatic ducts of the intrahepatic bile ducts; secondary branches are the slightly thicker bile ducts, which are the left inner lobe, left outer lobe, right anterior lobe and right posterior lobe bile ducts; tertiary branches refer to the bile ducts of each hepatic segment, which are the finer bile ducts. Clinically, many lesions can occur in the intrahepatic bile ducts, such as intrahepatic bile duct stones and intrahepatic bile duct cancer. Clinically, the blood supply to the intrahepatic bile ducts generally comes from the gastroduodenal artery, the common hepatic artery, and the right hepatic artery.