Whether renal function can be recovered after unobstructing hydronephrosis mainly depends on the time of hydronephrosis involvement. If the duration of hydronephrosis is short, renal function may recover if the obstruction is removed in time; if the duration of hydronephrosis is long, it may cause irreversible injury to the kidney and renal function usually cannot be recovered. If transient hydronephrosis leads to urinary tract obstruction and acute renal impairment, renal function may gradually decrease or even possibly return to normal if surgery intervenes in time to relieve obstruction. If the hydronephrosis is prolonged and has caused irreversible damage to the kidneys, even if the obstruction is lifted, the renal function injury still exists, and at this time, the renal function usually cannot be restored. If patients have hydronephrosis, it is recommended to go to regular hospitals in time and receive standardized treatment under the guidance of doctors.