Objective To evaluate the relationship of serum level of soluble suppression of tumorigenicity 2(sST2) with cardiac function in the elderly patients with acute myocardial infarction (AMI). Methods A total of 59 patients (≥60 years) with AMI within 24 h of symptom onset admitted in our department from March to December 2011 were subjected in this study. Immediately after admission, their serum levels of sST2 and N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured, Killip cardiac function class was analyzed, and echocardiography was performed within 48 h. Another 36 age-matched healthy subjects were recruited as normal controls. Results The serum level of sST2 was significantly higher in AMI patients than in control group [(36.2±21.3) vs (12.5±11.4)μg/L, P＜0.05]. In the AMI group, the sST2 level was positively correlated with NT-proBNP level (r＝0.585, P＜0.05), and negatively correlated with left ventricular ejection fraction (LVEF) (r＝-0.611, P＜0.05). Significant differences were seen in sST2 level between Killip Ⅰ and Ⅱ [(27.6±14.5) vs (38.0±20.6) μg/L, P＜0.05] and between Killip Ⅱ and Ⅲ＋Ⅳ [(56.5±25.0)μg/L, P＜0.05]. Conclusion The serum level of sST2 is significantly higher in AMI patients than in normal controls. The sST2 level is correlated with NT-proBNP level and LVEF, and also, in an increasing trend with the elevation of Killip grading, but NT-proBNP level has no such trend.