The anatomical complexity of the occurrence site of hilar cholangiocarcinoma and its local infiltrative growth characteristics, especially the easy upward invasion of the liver, make its surgical resection very difficult. In recent years, with the continuous progress of hepatic resection technology and vascular surgery technology, combined hepatic resection and vascular resection have significantly improved the radical resection rate of hilar cholangiocarcinoma, with an average of 34.8% (16%-64%) reported in large overseas or comprehensive literature, and the surgical safety and postoperative survival rate have also improved significantly. ～In China, the 5-year survival rate after radical resection of hilar cholangiocarcinoma was reported as 13.6% to 31.0%. Combined hemihepatectomy for hilar cholangiocarcinoma has the following obvious advantages. First, combined hemihepatectomy can improve the surgical resection rate, especially the radical resection rate, and thus improve the prognosis. The submucosal infiltration of hilar cholangiocarcinoma in the direction of bile duct is the most significant feature of its biological behavior. Even in the early stage of hilar cholangiocarcinoma before the infiltration of surrounding tissues and the occurrence of obstruction, the tumor often spreads submucosally in the direction of bile duct, and the scope of infiltration in the direction of intrahepatic is significantly larger than that in the direction of duodenum. This is the fundamental reason for the low radical resection rate and poor prognosis of hilar cholangiocarcinoma, especially for Bismuth type III or IV cases, in which the affected intrahepatic secondary bile ducts are often invaded by the tumor, and it is difficult to achieve the standard of radical resection of 5 mm without combined resection of the affected liver lobes. The radical resection rate of 73.6% (14/19) in the hemihepatectomy group was significantly higher than the radical resection rate of 40.9% (9/22) in the non-hepatectomy group, and the difference was statistically significant (P=0.035), while excluding the effect of Bismuth type I and II cases in the non-hepatectomy group, the radical resection rate of Bismuth type III or IV cases in the two groups was 73.6% (14/19), respectively. The difference was more statistically significant (P=0.005), with 73.6% (14/19) and 23.1% (3/13) for Bismuth type III or IV cases, respectively. Combined lobectomy to improve the radical resection rate has also been reported in the literature both nationally and internationally. Direct invasion of surrounding tissues is another growth feature of hilar cholangiocarcinoma, and it is common for Bismuth type III or IV lesions to reach the right and left hepatic ducts and then invade the immediately adjacent liver tissues. Among the surgically resected cases in our group, 14 cases (34.2%) had pathological confirmation of liver invasion; Zhao Jianxun et al. reported that the pathological report of liver tissue involvement after resection of hilar cholangiocarcinoma was as high as 54.3%, and concluded that radical resection should be a three-dimensional concept of the whole specimen being cancer-free around the whole area, not only the cancer-free bile duct cutting edge, and the radical effect of using hemihepatectomy is certain. In addition, the invasion of hilar vessels, especially portal vein, is a key factor limiting the radical resection of hilar cholangiocarcinoma, and the adoption of hemihepatectomy can remove the invaded vessels on the affected side together, which can improve the radical resection rate to a certain extent. Clinical practice proves that the absence of cancer in the surgical margin of hilar cholangiocarcinoma is the key point of radical surgical resection, which is the key factor to improve the postoperative survival rate of patients, and the combination of hemihepatectomy can improve the radical resection rate of hilar cholangiocarcinoma, thus improving the prognosis of patients and increasing the postoperative survival rate. There was no significant advantage in the survival rate of the hemihepatectomy group compared with the non-hepatectomy group in our cases, which may be related to the smaller number of cases and shorter follow-up time. For Bismuth type III-IV cases, after radical resection, the bile ducts to be anastomosed often reach the secondary or even higher bile ducts in the liver, and the number of bile duct breaks, thin walls, and adjacent blood vessels and liver tissues prevent the adjacent bile ducts from forming, thus making bile-intestinal anastomosis very difficult and requiring great workload and patience of the surgeon; Liang Lijian et al. Biliary fistula mostly occurs at the bile-intestinal anastomosis, and the enlargement of surgery increases the occurrence of biliary fistula, and the complex molding and numerous anastomoses are the root cause of biliary fistula. After combined hemihepatectomy, the number of bile duct stumps is significantly reduced, which simplifies the surgical operation of bile-intestinal anastomosis, and the reduction of the number of anastomoses may reduce the occurrence of biliary fistula and other complications. However, there was no advantage of the hemihepatectomy group over the non-hemihepatectomy group in terms of mean operative time, postoperative hospital stay and postoperative complications in this group of cases, and the reasons for this were analyzed: the simplified surgical operation of bile-intestinal anastomosis by hemihepatectomy might be offset by the operation of hemihepatectomy, and the advantage of the reduction in the number of anastomoses that might reduce biliary fistula would be offset by biliary fistula in the liver trauma after hemihepatectomy, making the mean operative time of hemihepatectomy longer than In the non-hemicohepatectomy group, postoperative complications (including biliary fistula) were also more frequent. In addition, hemihepatectomy allows good visualization of the hilar region, which facilitates exploration and surgical manipulation. The infiltration of hepatoportal cholangiocarcinoma tumor often constricts the hepatoduodenal ligament structure upward; and the jaundice caused by biliary obstruction often makes the liver enlarged and hardened, which makes the lesion, which is not easy to be exposed, extend further into the liver, making the exploration and surgical operation very difficult. Hepatic hemicolectomy allows better exposure of the retained intrahepatic secondary bile ducts, facilitating surgical exploration and providing adequate exposure and good space for further surgical operations such as bile duct formation and bile-intestinal anastomosis. Extensive hepatic resection in patients with severe jaundice and long duration will undoubtedly increase postoperative complications and mortality, how to improve surgical safety and minimize complications and mortality? We believe that necessary preoperative evaluation and preparation, excellent surgical technique, sufficient meticulousness and patience, and active and correct management during the perioperative period are the keys to reduce surgical complications and mortality. Ultrasound-guided external drainage of PTCD was performed in patients with severe jaundice (T-Bil>171 μmoL/L) and intrahepatic bile duct dilatation of more than 5 mm. Effective implementation of surgical PTCD to reduce yellowing can relieve biliary obstruction, reduce jaundice, improve liver function, and reduce postoperative complications and mortality after extensive hepatectomy, especially the occurrence of liver failure.Kawasaki et al. and Seyama et al. vice versa reported that the surgical mortality rate was 0-1.3% when treated with yellowing reduction before enlarged resection for hilar cholangiocarcinoma. Biliary drainage increases the chance of biliary tract infection, but for combined extensive lobectomy, especially for enlarged right hemicolectomy, preoperative biliary drainage to reduce jaundice is beneficial for recovery of liver function. it often takes 2-4 weeks or more after PTCD drainage until bilirubin levels are normal or near normal and hepatocyte function is restored. does postponing surgery affect prognosis? seyama et al. reported that postponing surgery did not affect the long-term outcome. Another advantage of indwelling PTCD is that liver function can be determined by observing the nature of the drained bile. Our experience is that thin and large drained bile, although the serum bilirubin can be significantly decreased, indicates that liver function is often poor, and postoperative liver insufficiency and other comorbidities are likely to occur, so for such patients, on the one hand, we should further strengthen the yellowing reduction and liver preservation therapy to prolong the drainage time as much as possible in order to improve liver function, and on the other hand, we should carefully choose extensive hepatectomy and/or combined resection of the intrinsic hepatic artery. Cholangiography via PTCD can reflect the extent of the lesion and determine the staging more economically and clearly, which is very important for guiding the surgical resection. In conclusion, combined hemihepatectomy for hilar cholangiocarcinoma can improve the radicality of surgery and improve the prognosis, but the long-term efficacy needs to be observed with further expansion of the number of cases and extension of the follow-up period.