The treatment of ureteral obstruction and hydronephrosis is as follows: 1. Define the cause of obstruction, and further perform ultrasound or CT examination to clarify whether the obstruction is caused by stones, tumors or inflammatory ureteral stenosis; 2. If the obstruction is caused by stones, extracorporeal shock wave lithotripsy or holmium laser lithotripsy can be chosen according to the location and size of the stones, so that the stones can be discharged from the body as soon as possible to relieve the obstruction and the hydronephrosis can be relieved naturally. If ureteral tumor is suspected to cause obstruction, further ureteroscopy should be performed to clarify the diagnosis and confirm whether the occupancy is benign or malignant, and then surgery should be performed to remove the obstruction, so that the hydronephrosis can be relieved naturally. If the stenosis is caused by infection or inflammation, systemic anti-infection treatment is recommended. After the recovery of inflammatory treatment, if ureteral patency can be restored, the hydronephrosis can be relieved naturally. If scarring stenosis occurs after inflammation, retrograde ureteral stenting or balloon dilation can be performed to relieve the fluid and drain the kidney.