Acute renal failure(ARF) is a serious complication after cardiac surgery. It is an important influential factor of increasing mortality, extending mechanical ventilation time and intensive care unit time, resulting in cognition functional impairment and respiratory function failure et al, and increasing cost of hospitalization. Extracorporeal circulation, intra-aortic balloon pump, renal inadequacy before surgery, diabetes and peripheral vascular disease are all risk factors of ARF after operation. These factors can lead to ARF by constriction of capacitance vessel, filling defect of renal and ischemia-reperfusion injury et al. Appropriate drug treatment, haemodialysis and hemofiltration could protect renal function and improve prognosis of ARF.