Objective To explore the appropriately operative chance , method, and perioperative management of coronary arterybypass grafting （CABG） in the patients with severe left main artery （LMA） stenosis with three-vessel-disease.Methods A total of296 patients with severe LMA stenosis with three-vessel-disease who underwent CABG surgery was analyzed retrospectively from 2003through 2013.Of them, 276 patients underwent conventional coronary artery bypass surgery on pump （ CCABG）and 20 patients underwentoff-pump CABG（ OPCAB）; 172 Patients was over 60 years old （58.1%）and 246 patients （83.10%） had concomitant diseasesincluding valve lesion, hypertension, diabetes, myocardial infarction, left ventricular aneurysm with septal defect , stroke, renal failure,and cancer.Left internal mammary artery use was in 281 patients （95.1%）; and 32 patients were implanted intra-aortic ballonpump（IABP） perioperatively.Results There were 7 cases（2.36 %） death of postoperative low cardiac output , ventricular fibrillation,cerebral infarction, renal failure, and multiple organ failure, respectively.Postoperative complications were low cardiac output ,respiratory failure , ventricular fibrillation, cereboembolism, cardiac tampomade, renal failure, stroke, and multiple organ failure.Afterfollow-up 2 to 84 months, there was 3 death in which 2 death of cardiac factors.Conclusions CCABG was a safe and effectivemethod in patients with severe LMA stenosis with severe three -vessel-disease.Preoperative insertion of IABP can certainly avoid the po -tential operative risk factor and significantly decrease the mortality and morbidity .