Abstract: Objective To investigate the efficacy, technique and surgeon fatigue of laparoscopic nephroureterectomy for the treatment of duplicated kidney and ureter with a modified stand-alone flexible ergonomics (SAFE) operation. Methods Retrospective analysis was performed using clinical data from 7 patients who underwent laparoscopic SAFE nephroureterectomy for duplicated ureter from July 2016 to December 2019. The operation duration, intraoperative blood loss, postoperative intestinal recovery time and residual renal function were analyzed. Meanwhile, surgeon fatigue degree was evaluated by the fatigue index. Results All the seven patients successfully finished operation without serious complications. The operation duration ranged from 115 to 175 min. The intraoperative blood loss ranged from 40 to 120 ml. The postoperative recovery time of intestinal function was 1-3 days. The average surgeon fatigue degree was low to intermediate. The residual renal function was good after 1-18 months follow-up visits. Conclusions The SAFE nephroureterectomy for duplicated kidney and ureter is safe and effective, with little incision and fast recovery. Surgeons feel less fatigue when sitting in comfort.