Objective:To explore the differences of risk factors and clinical characteristics between coronary artery disease (CAD) complicated with diabetes mellitus (DM) and CAD. Methods:A total of 1 277 patients who were diagnosed with CAD by coronary angiography (CAG) from 1 926 patients were divided into the CAD without DM group and the CAD complicated with DM group.Meanwhile,649 patients with no CAD diagnosed from the 1 926 patients by CAG were considered as the control group. The clinical characteristics and the related risk factors of the subjects were collected. Results:Among the three groups,the distributions of the gender,age,BMI,fasting blood glucose (GLU),apolipoprotein A (apoA),lipoprotein a,hypertension,cardiac color ultrasound of LVEF (%),smoking status,daily smoking,drinking status,the intensity of work and the usual frequency of exercise were significantly different (P < 0.05). For the CAD with DM and without DM groups,BMI,GLU,apoA,daily smoking were significantly different (P < 0.05). Multivariate Logistic regression analysis showed that,compared with the control group,male,age > 60 y,hypertension,smoking were associated with the increased risk of CAD. Meanwhile,male,age > 60 y,BMI≥24 (kg/m2),high levels of TC and smoking had a significantly increased risk of CAD with DM. Compared with the CAD without DM group,female,BMI≥24 and high levels of TG were associated with the increased risks of CAD with DM. Conclusion:Female,BMI≥24,blood lipid abnormality and 3 lesions of coronary artery might be the risk factors for CAD with DM. Many measures should be carried out to release these risk factors and to improve the life quality of patients with CAD with DM and the prognosis of CAD with DM.