Objective: To investigate the value of preoperative three-dimensional image reconstruction in the treatment of ureteropelvic junction obstruction (UPJO). Methods: We reviewed data on 40 patients (22 male cases,and 18 female cases) diagnosed with UPJO in Peking University First Hospital from May 2017 to April 2019. The median age was 26.5 years (IQR 23.25-38.75) years. There were 11 patients complicated with ectopic vessels,14 patients with kidney stones,3 patients with horseshoe kidney,and 6 patients with obstruction after pyeloplasty. All the patients underwent preoperative enhanced CT scan,and the CT data were reconstructed into three-dimensional image models. The obstruction position of ureteropelvic junction and the relationship between ureteropelvic junction and blood vessels and organs were observed by three-dimensional models to assist planning surgery. Thirty-seven patients underwent laparoscopic pyeloplasty (including 3 cases combined with pyelolithotomy with flexible cystoscope,1 case combined with pyelolithotomy by sun-style cystoscope, 1 case with laparoscopic ureter resection and anastomosis,3 cases of laparoscopic pyeloplasty of horseshoe kidney), 2 patients underwent laparoscopic ventral onlay lingual mucosal graft ureteroplasty, and 1 patient underwent robot-assisted laparoscopic pyeloplasty. Results: Three-dimensional CT image clearly showed the relationship between the obstruction of ureteropelvic junction and blood vessels and organs after three-dimensional reconstruction. The type,diameter,position and direction of the ectopic vessels could be observed clearly before operation according to the three-dimensional reconstruction model,and the number,size,location and shape of renal calculi or other masses,the number of involved renal calyces and the anatomical distribution in the renal pelvis and calyces could be also evaluated preoperatively. After comprehensive analysis of the above information,individualized operation plans were performed on the patients,all the 40 cases were successfully completed with the surgery without any transfer to open surgery. The average operative time was (129.91±37.90) min (range: 75 to 273), the average blood loss was (48.1±78.0) mL (range: 10 to 400), the average hospitality was (5.04±1.99) d (range: 2 to 10), and the average postoperative drainage time was (3.8±1.4) d (range: 2 to 8). Conclusion: The preoperative three-dimensional image reconstruction has a high clinical value in the treatment of ureteropelvic junction obstruction, and it is of great help to assist surgery planning and is worthy of further clinical promotion and application.