Abstract: Objective:To analyze the relationship between diabetes mellitus and coronary atherosclerotic plaque type, distribution and stenosis degree by dual-source CT coronary angiography (DSCTA). Methods:98 patients underwent coronary CTA examination with coronary heart disease (CHD), including 50 patients with diabetes mellitus and 48 patients without diabetes mellitus. The types, distribution, stenosis degree and main clinical manifestations of coronary atherosclerotic plaques were analyzed. Result:The distribution of coronary atherosclerotic lesions and plaque types in diabetic and non-diabetic patients had statistical significance (X²=7.01, P=0.03; X²=6.75, P=0.03). There was no significant difference in the incidence of degree and acute coronary syndrome, hypertension and hyperlipidemia (X²=1.86, P=0.60; X²=0.43, P=0.84; X²=0.52, P=0.47, X²=0.12, P=0.73). With the cut-off point of HbA1c ≥ 6.5% in diabetic patients, the incidence of clinical complications was statistically significant (X²=8.79, P=0.003). Conclusion:Coronary atherosclerosis in diabetic patients is more prone to calcification and mixed plaque. The incidence of double-vessel and multi-vessel lesions is significantly increased in diabetic patients. Diabetic patients are prone to clinical complications when HbA1c ≥ 6.5%.