Objective To observe the two-year prognosis of elderly patients with acute myocardial infarction (AMI) after coronary artery bypass graft (CABG), and investigate the factors that influence the prognosis. Methods A total of 70 patients suffering from AMI after CABG admitted in our hospital from June 2017 to June 2020 were recruited in this study. Their clinical data were collected, and the incidence of cardiovascular events were observed in a two-year follow-up. SPSS statistics 27.0 was used for data analysis. Student′s t test, Chi-square test, or Fisher exact test was employed for intergroup comparison depending on data type. Multivariate logistic regression model was adopted to analyze the factors influencing the prognosis of patients. Results There were 31 (44.3%) patients experiencing cardiovascular events during the two years′ follow-up. Logistic regression analysis showed that age >75 years (OR=6.465,95%CI 1.454-28.734), smoking after CABG (OR=5.874,95%CI 1.457-23.674), and thrombolysis in myocardial infarction (TIMI) flow grade <3 after percutaneous coronary intervention (PCI) (OR=9.353,95%CI 1.279-68.371) were risk factors for cardiovascular events, while PCI in native coronary artery (OR=0.153,95%CI 0.043-0.540) was a protective factor for the events in the elderly. Conclusion For the elderly patients suffering from AMI after CABG, age >75 years, smoking after grafting, and TIMI flow grade<3 after PCI increase the incidence, while PCI in native coronary artery reduces the incidence of cardiovascular events.