Objective To evaluate the clinical effects of pulsatile perfusion on the renal inadequacy during cardiopulmonary bypass ( CPB). Methods From January 2007 to May 2010, 55 patients with renal inadequacy undergoing open heart surgery were randomized into pulsatile group ( n = 28 ) and nonpulsatile group (n =27). Following parameters were examined: urea nitrogen , creatinine,uric acid, urine volume and blood gas, electrolyte and lactic acid before arteriae aorta opening. Results The urine volume during CPB was significant higher in the pulsatile group ( P ＜0. 01). The blood lactate level before arteriae aorta opening were significant lower in the pulsatile group ( P ＜0. 01). Conclusion The pulsatile flow is better than nopulsatile flow in oxygen metabolism of renal protection.