If severe hydronephrosis is lifted within a short period of time, renal function can usually return to normal completely, if the time is longer, it usually cannot return to normal completely. For severe hydronephrosis caused by various reasons, if the time is short and the renal function is still normal, then the hydronephrosis can be released in time, and the renal function can often be completely restored to normal. If the time of hydrocele is too long, the renal function often can not be completely restored to normal. In some patients, the renal function may even continue to decline, eventually leading to uremia and the need for renal replacement therapy. Therefore, patients with severe hydronephrosis must go to the hospital in time to improve the relevant examination and release the obstruction in time. If irreversible damage has occurred, reaching the level of uremia, it is necessary to carry out hemodialysis, peritoneal dialysis and other renal replacement therapy in a timely manner to maintain life.