Objective To investigate the diagnostic threshold value and diagnostic performance of high-sensitivity troponin T (hs-cTnT)for elderly patients with acute myocardial infarction(AMI).Methods 835 emergency department patients with chest pain were recruited in the study,then these patients were divided into elderly group (≥65 years old)and control group(<65 years old).Hs-cTnT concrentrations were compared between the two groups;The difference of hs-cTnT concentrations between AMI pa-tients and non-AMI patients were compared in elderly group and control group respectively;The optimal threshold values of the hs-cTnT for acute myocardial infarction were determined by receiver operating characteristic(ROC)curve.Results The hs-cTnT con-centrations of non-AMI patients in elderly group were 18.4(14.5-32.5)ng/L,which were higher than those of non-AMI patients in control group[3.2(3.0-8.2)ng/L],and the difference were statistically significant(P <0.05);The hs-cTnT concentrations of AMI patients in elderly group were 136.1 (51.6 - 384.1 )ng/L,which were higher than those of AMI patients in group 68.5 (25.6-217.1)ng/L,and the difference were statistically significant(P <0.05).According to the ROC curve,the optimal threshold value for AMI diagnosis in elderly group by using hs-cTnT was 32 ng/L,which was higher than that in control group(14 ng/L). The specificity and the positive predictive value of the optimal threshold value determined by ROC were apparently higher than the 99th percentile(P 99 )in elderly group respectively,the difference were statistically significant(P <0.05).Conclusion The hs-cTnT levels were positively related with age.The optimal threshold value of hs-cTnT for AMI(32 ng/L)was higher than the P 99 (14ng/L)in elderly group.