Abstract: Objective:To evaluate the therapeutic effects of low pressure perfusion ureteroscope in the treatment of middle or distal ureteral small calculus(diameter 0.6 cm).Methods:Seventy-one cases with middle or distal ureteral small calculus were treated with low pressure perfusion under a Wolf F8/9.8 semirigid ureteroscope,18 cases needed to use pneumatic ballistic lithotripsy during operation.Results:All operations were sucessful without any serious complications.Mucosal laceration occurred in 25 cases with moderate or serious ureteral stricture.Two cases with submucosal false passage were cured by detaining double J catheter.No mucosal avulsion and perforation of the serious complications was found.Conclusions:The effect of low pressure perfusion ureteroscope in the treatment of middle or distal ureteral small calculus is good,which can avoid the migrating of small calculus into the renal pelvis.