Objective] To analyse and study the causes and prevention of ureter injury related to ureteroscopy. [Methods] Sixteen cases of ureter injury caused by ureteroscopy since Aug. 1998 were reviewed and analyzed. [Results] Among 16 cases, ureteral meatus disruption 6 cases, ureter perforation 7 cases, sleeve exfoliation of mucous membrane 1 case, ureter fracture 1 case, tunnel under the mucous membrane 1 case. [Conclusions] Careful selection of appropriate case to undergo fragmentation by ureteroscopy was the premise to reduce untoward events related to ureteroscopy; keeping clear view and exact manipulation were critical during operation; stent could reduce ureter stricture.