There are more causes of ureteral stricture, and the common causes are ureteral infection, stones, polyps, congenital stricture, compression of the ureter, radiotherapy, etc. The clinical manifestations are related to the degree of stricture and the cause of the stricture. If the stenosis is mild, does not cause ureteral obstruction symptoms and does not produce hydronephrosis, there are often no uncomfortable symptoms in this case. If the stenosis is severe, it will lead to poor drainage of the urine secreted by the kidney on the stenosis side, and obvious hydronephrosis will occur, resulting in pain in the lower back and abdomen, and in severe cases, a mass will be felt in the lower back and abdomen, especially in children with congenital pelvic ureteral junction stenosis, and the long-term presence of hydronephrosis may even lead to inflammation of the renal pelvis, pus accumulation in the kidney, stone formation, and thin kidney cortex, which will affect the kidney function and cause symptoms such as back pain and fever. The symptoms include back pain and fever. If the ureteral stenosis is caused by stones, it is possible to have symptoms such as hematuria and pain. In summary, if the symptoms of ureteral stenosis are directly related to the degree of stenosis and the speed of onset, ureteral stenosis will not have any uncomfortable symptoms if it is not obvious, but if the stenosis is heavy, it will cause hydronephrosis and pus accumulation in the kidney, resulting in uncomfortable symptoms such as lumbar abdomen, lumps and fever.