If the cause is pelvic ureteral junction stenosis, which is a congenital disease, it does not develop in the early stage, but in the middle age, mild hydronephrosis can be treated by observation. The success rate is about 90%. If the stone is caused by a stone, in the upper segment, percutaneous nephrolithotomy is feasible; in the middle segment, laparoscopic ureterotomy is feasible; in the lower segment, ureteroscopic lithotripsy is feasible. If it is caused by tumor, young patients, for good renal function and no threat of underlying kidney disease, laparoscopic renal GIPOSON or open ureterectomy with partial cystectomy is feasible. For poor renal function, with underlying disease threats such as diabetes, hypertension, nephritis, etc., it is recommended to preserve the kidney and deal with the tumor. If the disease is caused by inflammation, the treatment is the same as the method for stenosis of the pelvic ureteral junction. If the tumor is advanced and caused by compression, it is better to perform percutaneous nephrostomy or internal DJ tube implantation to save the kidney, relieve the symptoms and create conditions for further treatment of the tumor.