Abstract: Objective To analyze the effect of high density lipoprotein-C（HDL-C） on type 2 diabetes mellitus（DM） accompanying coronary atherosclerosis.Methods Two hundred and twenty-seven patients with type 2 DM diagnosed with coronary atherosclerosis by coronary arteriongraphy（CAG） and undergone CAG at least after 6 months were enrolled in this study.The patients were divided into group A and group B according to their HDL-C.HDL-C in patients of group A was increased or unchanged and decreased in patients of group B.Results The progression rate of coronary atherosclerosis was 20.6% in group A and 36.5% in group B（P＜0.01）.The incidence of angina pectoris was 12.2% in group A and 15.6% in group B（P＜0.05）.The target lesion revascularization was 1.5% in group A and 3.1% in group B（P＜0.01）.Conclusion HDL-C is an independent risk factor for coronary atherosclerosis in patients with type 2 DM.