Abstract: ［Abstract］Objective To investigate the application value of a pressure-measuring and stone-extracting ureteral access sheath （UAS） used together with negative pressure suction system during flexible ureteroscopy in the treatment of renal caculus．Methods　A retrospective analysis was performed on the 98 cases of renal caculus who received flexible ureteroscopic holmium laser lithotripsy （FURS）in the Department of Urology of the Kunming General Hospital of Chengdu Military Command from November 2014 to September 2015, and the enrolled cases were divided into two groups: group A and group B. The new UAS was used in group A combined with vacuum suction during lithotripsy, and simple manometry type UAS was used in group B. The infusion pump flow rate of 0.2 L /min was set in the operation， the perfusion pressure limit was set to 100 mmHg， the suction pressure of group A was 10 kPa. Perfusion flow rate and pressure was adjusted in a timely manner based on the clear vision and the internal pressure force on the kidney. Then we recorded and compared the internal pressure and variation trend of renal and perfusion time of two groups. Results Two groups of patients were successfully completed surgery .The renal pressures in group A were adjusted duly and were lower than the that in group B in the whole process of operation. The average renal pressure in group A was 10.88±5.911mmHg. The average renal pressure in group B was 20.10±7.68 mmHg，the pressure control was difficult and unsteady．Conclusion　The new type of UAS in the flexible ureteroscopic holmium laser lithotripsy（FURS）can make the renal pressure in surgery controllable and is safe for the FURS.