Objective:To compare the performance and surgical outcomes of disposable digital flexible ureteroscope with a reusable fiberoptic flexible ureteroscope in treatment of upper urinary stones.Methods:A prospective, multicenter, single-blind and randomized controlled study was performed from April 2018 to December 2018. Eligible patients were randomized, in a ratio of 1∶1, to either experimental group or control group. The inclusion criteria for the study were: aged 18-60 years, solitary upper urinary stone or multiple stones with stone size less than 2 cm, absence of urinary tract infection (UTI) or UTI was controlled, normal liver and renal function. Exclusion criteria included: patients with congenital anomalies, calyceal diverticular stone, IP angle less than 30°, renal insufficiency. pregnancy or lactation, cardiopulmonary function abnormality and coagulation abnormalities. Patients in experimental group received ureteroscopy through a disposable digital flexible ureteroscope (PU3022A, PUSEN), while patients in control group received ureteroscopy through a reusable fiberoptic flexible ureteroscope (Flex-X2, STORZ). The primary endpoint was the high-quality rate of images during the operation. The secondary endpoints included success rate of fragmentation and postoperative complication rates.Results:93 patients were recruited, and 90 of them were finally complete the study (i.e., 45 patients in each group). The demographic and preoperative parameters were comparable between the two groups except the stone size in patients with solitary stone. The high-quality rate of images was significantly higher in experiment group than that in control group (100.0% vs. 15.6%, P<0.001). There were no significant differences in terms of success rate of fragmentation(68.9% vs. 71.1%, P=0.818), hemoglobin dropped (3.91 g/L vs. 3.62 g/L, P=0.880), serum creatinine changed, and postoperative complication rates(6.7% vs.6.7%, P=1.000). Conclusions:Disposable digital flexible ureteroscope achieves similar surgical outcomes to the reusable fiberoptic flexible ureteroscope with a better quality of endoscopic images.