Objective:To explore the clinical characteristics of elderly patients with type 2 diabetes mellitus (T2DM) complicated with coronary atherosclerotic heart disease (CHD) and analyze the risk factors of CHD in patients with T2DM.Methods:Using the method of retrospective cohort study, 406 elderly male patients with T2DM (≥75 years old) admitted to Xinhua Hospital Affiliated to Shanghai Jiaotong University from January 2017 to January 2020 were selected and divided into T2DM without CHD group (165 cases) and T2DM with CHD group (241 cases). The clinical characteristics in elderly patients with T2DM complicated with CHD and risk factors for CHD were analyzed.Results:The age ((86.78±5.35 )years old), course of T2DM((12.32±0.46) years), fasting blood glucose(FPG)((7.64±2.81) mmol/L), hemoglobin a1c (HbA1c)((7.59±1.21)%), the proportion of hypertension(84.65%(204/241)), D-dimer((0.50±0.13) mg/L), the incidence of thromboembolic events(46.06%(111/241)), blood serum creatinine ((94.81±12.70) μmol/L), urea nitrogen((8.31±4.46) mmol/L), uric acid((376.44±116.01) μmol/L) in T2DM with CHD group were higher than those in T2DM without CHD((78.51±4.81)years old, (10.66±0.67)years, (6.84±2.19) mmol/L, (7.02±2.15)%, 63.03%(104/165), (0.21±0.04 ) mg/L, 13.33%(22/165), (83.01±14.40) μmol/L, (6.79±2.89) mmol/L, (333.56±95.15) μmol/L ), and the differences were statistically significant( t=15.908, t=2.042, t=3.055, t=3.088, χ 2=23.828, t=5.059, χ 2=42.098, t=2.401, t=4.188, t=4.075; all P<0.05). The total bilirubin(TBil)(8.80(6.60, 11.60) μmol/L), glomerular filtration rate(GFR)((76.49±29.80) mL/(min·1.75 m 2)) in T2DM with CHD group were lower than those in T2DM without CHD group (11.25(8.23, 15.28) μmol/L, (91.81±28.31) mL/(min·1.75 m 2)), the differences were statistically significant( Z=2.304, t=5.126; all P<0.001). The total cholesterol((3.84±0.85) mmol/L), low-density lipoprotein cholesterol(LDL-C)((2.12±0.68 ) mmol/L) in T2DM with CHD group were lower than those in T2DM without CHD group((4.10±1.00) mmol/L, (2.45±0.85) mmol/L), the differences were statistically significant( t=2.828, 4.156; all P<0.05). The rate of starting lipid-lowering and stable plaque treatment in T2DM with CHD group (82.57%(199/261))was higher than that in T2DM without CHD group(42.42%(70/165)), and the difference was statistically significant (χ 2=70.614, P<0.001). Influenced by lipid-lowering therapy, the total cholesterol and LDL-C in T2DM patients with CHD were significantly decreased.Logistic regression analysis showed that age elevated( OR 1.346, 95% CI 1.263-1.434, P<0.001), elevated hemoglobin a1c concentration( OR 1.427, 95% CI 1.140-1.785, P=0.002), complicated with hypertension( OR 3.534, 95% CI 1.684-7.418, P=0.001), elevated D-dimer concentration( OR 3.969, 95% CI 1.227-12.841, P=0.021)and elevated uric acid concentration( OR 1.005, 95% CI 1.001-1.008, P=0.006)were independent risk factors for CHD in elderly male patients with T2DM. Conclusion:Elderly patients with T2DM complicated with CHD are more likely to be in hypercoagulable state, more likely to have thromboembolic events, and more obvious renal function damage.Poor fasting blood glucose control and decreased total bilirubin concentration are the influencing factors of CHD in elderly male patients with T2DM.Age elevated, elevated hemoglobin a1c concentration, complicated with hypertension, elevated D-dimer concentration and elevated uric acid concentration are independent risk factors for CHD in elderly male patients with T2DM.