The effect of preoperative Double-J(DJ)ureteral stenting before flexible ureterorenoscopy(FURS)in the treatment for urinary stones was evaluated.We retrospectively enrolled 306 consecutive patients who underwent FURS from Jan.2014 to Dec.2017.All the patients were classified into two groups according to whether they had DJ ureteral stenting before FURS.Baseline characteristics(age,sex,stone location,stone size,surgical success rate,operation time,stone-free rate of the first day after surgery,stone-free rate of the first month after surgery,total complication rate)were compared using Chi-square test for categorical variables and Kruskal-Wallis test for continuous variables.In total,306 patients were included in this study.The group of DJ stenting before FURS included 203(66.3％)patients,and non-DJ stenting before FURS was observed in 103(33.7％)patients.The group of DJ stenting before FURS was significantly associated with a shorter operation time(53.8 vs.59.3 min,P＜0.001),a higher stone-free rate of the first day after surgery(69.0％vs.51.5％,P=0.003).However,statistical significant differences were not found in the age,sex,stone location,stone size,surgical success rate,stone-free rate of the first month after surgery(89.2％vs.81.6％,P=0.065)and total complication rate(5.4％vs.9.7％,P=0.161)between the two groups.Preoperative DJ ureteral stenting before FURS could reduce the operation time and increase stone-free rate of the first day after surgery.However,it might not benefit the stone-free rate of the first month after surgery and reduce the complication rate.Preoperative DJ stenting should be not routinely performed.