Abstract： Objective To investigate whether the serum level of cardiac troponin Ⅰ (cTnI) at the 7th day after acute myocardial infarction (AMI) is a predictive factor of the prognosis of patients. Methods One hundred and sixty-one patients with AMI were divided into three groups (emergency percutaneous coronary intervention (PCI) group, delayed PCI group and drug therapy group). Thirty patients without organic heart disease as a control group. The levels of cTnI at the 7th day after AMI were measured by chemoluminescence technique. Major cardio-vascular events (MACEs) were recorded on admission and during follow-up period. The correlation between cTnI serum levels and the incidence of MACEs was analyzed. Results Compared to the control group, the levels of cTnI were significantly increased at the 7th day in AMI patients (P<0.01). The total negative-conversion rate on the 7th day was 39.1%, the negative-conversion rate was higher in emergency PCI group compared to delayed PCI group and drug therapy group (68.6% vs 36.1% and 28.9%, P<0.01). The incidence of MACEs in AMI patients with cTnI<1.5 μg/L was significantly lower than that in AMI patients with cTnI≥1.5 μg/L(1.6% vs 34.7%, P< 0.01). The serum level of cTnI in AMI patients with MACEs was higher than that in AMI patients without MACEs (P<0.01). The incidence of MACEs was correlated with the serum level of cTnI in AMI patients (P<0.05). The incidence of MACEs in AMI patients with cTnI>9.0 μg/L was the highest among all AMI patients (P<0.05). Conclusions The serum level of cTnI at the 7th day in patients after an episode of AMI is an independent predictor for the prognosis.