Treatment of hydronephrosis caused by urethral stones: 1. If the stone volume is not large, not more than 1cm, and the hydronephrosis is a small amount, i.e., the ultrasound examination of the renal pelvis separation is less than 2cm, then in vitro lithotripsy treatment is recommended. During the period of lithotripsy, pay attention to the regular rechecking of the amount of water retention, if the amount of water retention decreases, then continue the extracorporeal lithotripsy and stone removal treatment. If the amount of fluid increases, surgery is recommended. 2. If urethral stones cause a medium to large amount of fluid in the kidney, direct transurethral surgery, such as holmium laser lithotripsy or transurethral pneumatic ballistic lithotripsy, is recommended to remove the stones and relieve the fluid after the obstruction is removed. 3. If the effect is not good, it is recommended to perform lithotomy and resection of the stenosis and end-to-end ureteral anastomosis, so as to avoid repeated stenosis caused by stones in the future, which may lead to secondary hydronephrosis.