Aim To investigate the relationships between the changes in serum visfatin and coronary artery lesions, cardiac function in patients with acute myocardial infarction, and their chinical significance. Methods Acute myocardial infarction （AMI） patients with emergency percutaneous coronary intervention were picked out as test group （AMI group, n＝30）, including twenty-two men and eight women whose average age was 54.77±10.09. The degree of coronary artery lesions was assessed by the number of coronary artery lesions and Gensini integral. Meanwhile, the patients undergoing coronary angiography without any artery lesions were as control group （n＝30）, including twenty men and ten women whose average age is 54.07±11.07. Serum level of visfatin was measured by enzyme-linked immunosorbent assay （ELISA） at pre-operation and 24 hours after operation Left ventricular ejection fraction （LVEF） and left ventricular end-diastolic diameter （LVEDD） were measured by echocardiography. Results Serum levels of visfatin at both time points （pre-operation: 80.82±7.63 μg/L, 24 hours after operation: 91.96±7.37 μg/L） were significantly higher than that of control group （19.32±4.37 μg/L） （P<0.01）. Compared with pre-operative level, serum visfatin level was significantly increased at 24 hours after operation （P<0.01）. Serum levels of visfatin from different numbers of coronary artery lesion were: single-lesion: 72.85±2.56 μg/L, double-lesions: 82.24±5.77 μg/L, multi-lesions: 88.22±6.07 μg/L） Serum levels of visfatin from different stenosis degree were: mild: 74.58±4.40 μg/L, moderate: 80.13±4.71 μg/L, severe: 87.57±6.39 μg/L The differences between groups were statistically significant （all P<0.05）. Compared with control group, LVEF in AMI group was significantly lower （P<0.01），but LVEDD wasn’t significantly different. Serum level of visfatin was positively correlated with coronary artery lesion counts, coronary artery lesion Gensini integral （r＝0.754, r＝0.672, P<0.01）, whereas was negatively correlated with LVEF （r＝－0.459, P<0.01） in AMI group. Conclusion Serum level of visfatin can be used as an indicator to conjecture the severity degree of coronary artery lesion in patients with acute myocardial infarction.