The invention relates to a surgical instrument. A ureter nephroscope with a bendable head end comprises an operating body which is connected with a nephroscope tube. The operating body comprises a nephroscope body, an assembling and disassembling mechanism and a retractable mechanism all of which are sequentially connected. The nephroscope tube comprises an inserting part, a bending part and a head end part all of which are sequentially connected. The inserting part is connected with the nephroscope body, the nephroscope tube is sleeved with a sheathing tube, the length of the sheathing tube is smaller than that of the nephroscope tube, and the retractable mechanism is located at one end of the sheathing tube and is connected with the nephroscope body through the assembling and disassembling mechanism. The ureter nephroscope with the bendable head end integrates the functions of a hard ureter nephroscope and a soft ureter nephroscope, and can be fast mounted and dismounted so that all components can be disinfected conveniently, the ureter nephroscope can be inserted into the ureter easily and can be inserted into kidney calices, especially into the lower kidney calices smoothly, and the situation inside the lower kidney calices can be well observed. The technical problems that an existing ureterocope in the prior art is inserted into the ureter difficultly, the situation inside the lower kidney calices cannot be well observed, the treatment cannot be well carried out, and the components cannot be fast mounted, dismounted or disinfected are solved.