Aim To detect the plasma AnnexinⅤexpression rate in elderly patients with acute coronary syndrome (ACS), and explore the correlation between AnnexinⅤexpression rate and cardiovascuar risk factors, fibrinogen (FIB), D-dimer, platelet aggregation rate (PAR). Methods 156 patients who were successfully examined by coronary angiography were recruited in our hospital from December 2014 to May 2016. These patients were divided into ACS group (n＝88), stable angina pectoris (SAP) group (n＝36) and control group (n＝32). The AnnexinⅤexpression rate and PAR were detected by flow cytometry instrument, the levels of FIB and D-dimer were detected by immunofluorescence method determination. Detailed information were recorded in age, history of smoking, diabetes, hypertension and so on.Different groups were compared to analyse the correlation between the AnnexinⅤexpression rate and cardiovascuar risk factors, FIB, D-dimer, PAR. Results The differences of AnnexinⅤexpression rate in ACS group were statistically significant compared with SAP group and control group (P＜0.05 or P＜0.01), but there was no statistically significant difference between SAP group and control group (P＝0.487). When the area under the ROC curve (AUC) was 0.876, the cut-off point was 29.36%, the sensitivity and specificity of diagnosis of ACS were 80.1% and 79.9%. The AnnexinⅤexpression rate in ACS group had a positive correlation with plasma FIB (r＝0.468, P＝0.047), D-dimer (r＝0.451, P＝0.040), PAR (r＝0.531, P＝0.010), smoking (r＝0.510, P＝0.009), hypertension (r＝0.506, P＝0.012) and diabetes (r＝0.493, P＝0.026). Conclusion The plasma AnnexinⅤexpression rate in elderly patients with ACS were positively correlated with diabetes, hypertension, smoking, FIB, D-dimer and PAR, which may be helpful to predict the occurrence and clinical risk of ACS.