Ureteral stent, also known as D-J Catheter or Double J Catheter, is the most commonly used tool in the treatment of various benign and malignant urinary system diseases. One end of the ureteral stent is located in the kidney and the other end in the bladder. Ureteral stent has the function of supporting, expanding and internal drainage of the ureter. It can dilate the ureter and relieve the temporary obstruction caused by ureteral inflammatory edema, and prevent ureteral stricture and ureteral obstruction caused by small calculus after operation.