The double J tube is usually removed 2~4 weeks after cystectomy, and usually should not be placed for more than three months, otherwise the catheter may deteriorate and break easily. Double J tube is widely used in urological surgery, applicable to kidney stones, ureteral stones, hydronephrosis, renal transplantation, benign tumors of the kidney and ureter and other upper urinary tract surgery, as well as ureteral stenosis of the expansion of the therapeutic process, which implanted in the ureter can play an important role in the drainage of urine, to prevent ureteral stenosis and adhesion and blockage. If the surgical damage is small or the patient has symptoms such as frequent urination, urgency of urination, and heavier pain in the lower back after insertion of the double J-tube, the double J-tube can be removed earlier, usually 2 to 4 weeks after the operation; if the patient does not have any discomfort and the wound recovery time after the operation is long, the double J-tube can be removed later at the discretion of the patient, for example, 4 weeks after the operation. The specific removal time of double J tube after cystectomy is subject to the guidance of professional doctors, if there is any discomfort, timely follow-up.