Most of the ureteral stents are placed after ureteral surgery to dilate the ureter, and some of them may cause certain hazards after the placement of ureteral stents, mainly including ureteral injury, stent displacement, stone formation and so on. 1. Ureteral injury: During the placement process, there is a possibility that the ureteral wall may be scratched, or the ureter may rupture due to excessive dilatation. 2. Stent displacement: loose stent after placement may cause displacement, causing obstruction or damage to the surrounding tissues and organs. 3. Stone formation: Abnormal flow of urine around the stent may lead to stone deposition, which may further cause urinary tract obstruction. In addition, long-term placement of the stent may be complicated by infection, adhesion and other hazards. After the ureteral stent is placed, once the corresponding area of pain and other discomforts, we should consult a doctor in time for observation and standardized treatment under the guidance of clinicians.