This study evaluates the safety and efficacy of the suctioning flexible ureteroscopy(SF-URS) with automatic control of renal pelvic pressure for the treatment of upper urinary calculi using a prospective, randomized design. Half of participants will receive suctioning flexible ureteroscopy with automatic control of renal pelvic pressure, while the other half participants will receive retrograde intrarenal surgery using the classic flexible ureteroscopy.