Objective To analyze the prognostic factors in the postoperative patients with prolonged mechanical ventilation after extracorporeal circulation.Methods From Oct 2004 to Oct 2007，35 cases of postoperative patients after extracorporeal circulation required mechanical ventilation for ≥24 hours in ICU were enrolled.The patients were divided into death group and survival group.Preoperative variables including blood glucose，serum albumin，creatinine and ejection fraction（EF），intra-operative variables such as cardiopulmonary bypass（CPB） duration，aortic cross clamp（ACC） time，blood transfusion，and postoperative variables such as vital sign arrival at ICU，renal function，drainage in first 24 hours，APACHEⅡ score，ventilation duration were analyzed retrospectively.Results There were significant differences in blood glucose，serum albumin，EF，CPB，ACC，fresh frozen plasma transfusion，APACHEⅡ，creatinine，APTT and oxygenation index between the death group（12 cases，34.29%） and the survival group（23 cases，65.71%）.Stepwise logistic regression analysis indicated that EF（OR=0.7973，95%CI 0.6417-0.9906） and APACHEⅡ（OR=1.8588，95%CI 1.1071-3.1210） were predictors of prognosis.Conclusions High mortality is found in postoperative patients after extracorporeal circulation with prolonged mechanical ventilation.The main predictors of prognosis were EF and APACHEⅡ.It’s important to assess preoperative condition for cardiac surgical patients completely and provide more intensive perioperative care.