Aim To investigate the clinical characteristics of acute myocardial infarction (AMI) patients with atrial fibrillation (AF). Methods From January 2014 to December 7,7 AMI inpatients admitted to the Department of Cardiology of Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology were enrolled. According to the patient's previous history and electrocardiogram diagnosis during hospitalization, the patients were divided into AMI with AF group (78 cases) and AMI without AF group (699 cases). The basic information, cardiovascular risk factors, biochemical indicators, echocardiography, coronary angiography and other data of the two groups were collected for statistical analysis. The differences of clinical characteristics were compared between the two groups. Results The age, smoking history, stroke history, chronic kidney disease history and ventricular arrhythmia incidence in AMI with AF group were significantly higher than those in AMI without AF group (P＜0.05). The hemoglobin, red blood cell count, triglyceride and estimated glomerular filtration rate in AMI with AF group were significantly lower than those in AMI without AF group, while the levels of serum uric acid, urea nitrogen, creatinine, cystatin C, brain natriuretic peptide and high-sensitivity C-reactive protein were significantly higher than those in AMI without AF group (P＜0.05). Echocardiographic results show that compared with AMI without AF group, the left atrium diameter and right atrium diameter increased significantly (P＜0.01), and the left ventricular ejection fraction decreased significantly (P＜0.05), in AMI with AF group. There was no significant difference in the results of coronary angiography between the two groups (P＞0.05). Conclusion The incidences of ventricular arrhythmia and heart failure are high in AMI with AF patients, and are prone to suffer from anemia and chronic kidney disease.