Water deprivation test was done in 44 healthy elderly persons, 26 were male, and 18 were female. They were deprived of the intake of water for 25 hours. The results showed that the maximal renal concentration function both in the elderly males and females was 887 ± 91 mmol / L and 888 ± 127 mmol / L respectively. The renal excretion of waste products in 24 hours both in the elderly males and females was 815+170 mmol / d and 620+132 mmol / d respectively. On the basis of point estimation, the minimal essential urine volume per day in the elderly males and females was 926 ml / d and 708 ml / d respectively, if the daily urine volume of the elderly is less than this level, then, the metabolic products generated per day can not be excreted by the kidney, and it would result in disorders of internal environment. Therefore, the oliguric standard in elderly males and females must be less than 926 ml / d and 708 ml per day respectively. Water deprivation test was done in 44 healthy elderly persons, 26 were male, and 18 were female. They were deprived of the intake of water for 25 hours. The results showed that the maximal renal concentration function both in the elderly males and females was 887 ± 91 mmol / L and 888 ± 127 mmol / L respectively. The renal excretion of waste products in 24 hours both in the elderly males and females was 815 + 170 mmol / d and 620 + 132 mmol / d respectively. On the basis of point estimation, the minimal essential urine volume per day in the elderly males and females was 926 ml / d and 708 ml / d respectively, if the daily urine volume of the elderly is less than this level, then, the metabolic products generated per day therefore, the oliguric standard in elderly males and females must be less than 926 ml / d and 708 ml per day respectively.