Objective To explore the application value of perihilar surgery technique in the reoperation of biliary dilatation of central large intra- and extra-hepatic bile ducts above the hilar convergence. Methods The retrospective cross-sectional study was conducted. The clinical data of 3 patients with biliary dilatation of central large intra- and extra-hepatic bile ducts above the hilar convergence who underwent the reoperation in the Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine from August 2017 to January 2018 were collected. All three patients had been collected a detailed previous surgical history. After preoperative lab and imaging examinations, evaluation of liver function, residual liver volume and general condition were done, then 3 patients underwent left hemihepatectomy + dilated right hepatic duct and extrahepatic bile duct resection, right anterior and posterior hepatic duct reconstructive surgery and Roux-en-Y anastomosis of the jejunum. The surgical procedures followed as: intra-abdominal adhesions separation, extrahepatic antergrade dissection of porta hepatis, transverse cutting the dilated extrahepatic bile duct, split the cantlie line, exposure of the hilar plate, left hemihepatectomy, dilated right hepatic bile duct resection, right anterior and posterior hepatic duct remodeling and biliary-enteric anastomosis. Observation indicators included: (1) surgical and postoperative recovery; (2) follow-up. Follow-up using outpatient examination and telephone interview was performed to detect general condition, complications, liver function and residual choledochal cysts up to May 2018. Results (1) Surgical and postoperative recovery: All the 3 patients underwent choledochal cysts resection + left hemihepatectomy + dilated right hepatic duct + right anterior and posterior hepatic duct reconstructive surgery and Roux-en-Y anastomosis of the jejunum using the perihilar surgery technique and extrahepatic anterograde combined by intrahepatic retrograde dissection method exposing portal hepatis. There was no perioperative death. The operation time and volume of intraoperative blood loss in 3 patients were 435 minutes, 490 minutes, 395 minutes and 250 mL, 300 mL, 200 mL, respectively. There was no intraoperative blood transfusion. Three patients had no bleeding and abdominal liver function. One patient with bile leakage and delayed gastric emptying at 1 week postoperatively received puncture drainage, gastrointestinal decompression, gastric lavage with hypertonic saline, acupuncture and total parenteral nutrition, then bile leakage was cured after 3-week therapy, gastric motility was improved after 5-week therapy, and then gastric tube was removed. The abdominal drainage tube was removed at 3 weeks postoperatively in 1 patient and at 1 week postoperatively in 2 patients. The postoperative gross specimen examinations showed intra- and extra-hepatic bile duct dilatation in 3 patients, including 2 combined with choledocholithiasis and 1 with left intrahepatic bile duct cancer. The postoperative pathological findings showed that 3 patients had intrahepatic bile duct cystic dilatation with chronic inflammation, peripheral small bile duct hyperplasia with inflammatory cell infiltration, 1 of which had intrahepatic intraductal papilloma with high grade intraepithelial neoplasia. One and 2 patients were discharged from hospital at 7 weeks postoperatively and 2 weeks postoperatively, respectively. (2) Follow-up: All 3 patients were followed up for 4-8 months. During the follow-up, patients had good general condition and no symptoms of cholecystitis such as abdominal pain, chills and fever, liver function was normal, and no residual bile duct cyst was found by enhanced scan of CT. Conclusion The perihilar surgery technique and extrahepatic anterograde combined by intrahepatic retrograde dissection method exposing portal hepatis for the treatment of biliary dilatation of central large intra- and extrahepatic bile ducts above the hilar convergence can increase the radical resection rate and surgical efficacy. Key words: Biliary dilatation; Perihilar technique; Central large hepatic bile duct above the hilar convergence; Extrahepatic anterograde combined by intrahepatic retrograde dissection method exposing portal hepatis; Surgical procedures, operative