The present study was designed to examine whether water extract of Alpiniae oxyphyllae Fructus (AAO) has an effect on renal functional parameters in association with the expression of water channels and sodium potassium pump in ischemia/reperfusion-induced acute renal failure (ARF). Polyuria caused by down-regulation of renal AQP-2, 3 in the ischemia/reperfusion-induced ARF rats was markedly restored by administration of AAO (200 mg/kg/day p.o.) with restoring expression of AQP-2, 3 in the kidney. The expression of Na,K-ATPase α1 subunit was also restored in the ischemia/reperfusion-induced ARF rat by administration of AAO. The renal functional parameters including urinary sodium excretion, urinary osmolality, and solute-free reabsorption were also markedly restored in ischemia-ARF rats by administration of AAO. In histopathologic study, administration of AAO improved tubular damage such as necrosis of tubular segment. Ischemia/reperfusion-induced ARF decreased the expressions of AQP-2, 3, and Na,K-ATPase in renal medulla. However, administration of AAO markedly restored the expression levels of AQP-2, 3 and Na,K-ATPase. Taken together, the present study suggested that A. oxyphyllae ameliorates the urine concentration and renal functions in ischemia/reperfusion-induced ARF, through the restoring of AQP-2, 3 and Na,K-ATPase.