When urine volume is low, we should first determine whether it is physiological or pathological oliguria. 1, physiological oliguria is often seen in hot weather, too much water evaporation or less hydration, insufficient rehydration, etc. If the above situation exists, it is recommended to drink more water appropriately, and patients who cannot drink can be rehydrated intravenously to observe whether the urine volume is normal. 2, if the oliguria is not caused by factors such as drinking water or evaporation, it is recommended to further perform Ultrasound of the urinary system to check whether there is obstruction or whether there are substantial changes in the kidneys. If the kidneys are not working due to various pathogenic factors damage and produce less urine, further inpatient examination is needed to give symptomatic treatment such as diuresis and protection of kidney function.3. If there are stones in the kidneys, ureteral stones or tumors that cause urine to stay in the body instead of being discharged, such as hydronephrosis and urinary retention, indwelling catheterization needs to be given and then the primary disease should be dealt with, such as extracorporeal shock wave lithotripsy or tumor removal, etc., before urine output can be ensured to be restored.