Objective: To analyze the risk factors of prolonged mechanical ventilation(PMV) after coronary artery bypass graft surgery(CABG) with the purpose of improving the management of these patients. Methods: The preoperative,operative and postoperative clinical data of 170 patients,who underwent CABG in 2010,were retrospectively analyzed for the risk factors of PMV. Binary Logistic regression models were used to assess the affection of factors. Results: Statistics show that the elder age,currently smoker,left ventricular ejection fraction(LVEF),duration of operation,volume of chest drainage and postoperative complications were risk factors of PMV,meanwhile LVEF,duration of operation,volume of chest drainage and postoperative had extremely affection. Conclusion:Greater importance should be attached to healthcare education,preoperative heart function regulation,lower duration of operation,reduce postoperative chest drainage and better preservation of organs during operation to decrease the rate of PMV and optimize the clinical quality.