Objective To explore effect of miR-126 on apoptosis of myocardial cells in rats with acute myocardial infarction (AMI). Methods AMI model was established by ligation of left anterior descending branch of coronary artery. The survivors were randomly divided into 3 groups:AMI group, NC group and miR-126 group. the NC group and miR-126 group were injection of lentiviral transfection of miR-126 mimics NC and miR-126 mimics. The sham operation group was left anterior descending coronary artery without ligation. The rats' cardiac function was recorded. Apoptosis index and infarct size of myocardium was detected by TCC method and in situ end method (TUNEL), respectively. The activity of cysteinyl aspartate specific proteinase 3 (Caspase 3) and Caspase 8 were determinated by colorimetry. The expression of Bcl-2, Bax was assayed by Western-blot. The expression of Fas and Fas-L mRNA was detected by RT-PCR. Results Compared with sham operation group, left ventricular ejection fraction (LVEF) and left ventricular long axis shortening fraction (FS) was increased, left ventricular end diastolic diameter (LVDd) and left ventricular end systolic diameter (LVDs) was decreased, apoptosis index was increased, myocardial infarction area increased, the activity of Caspase 3 and Caspase 8 was increased, the expression of Bax protein was upregulated, the expression of Bcl-2 protein was downregulated, the expression of Fas and Fas-L mRNA was increased in AMI and NC group, the difference was statistically significant (P<0.01). Compared with AMI and NC group, miR-126 could reverse the change, the difference was statistically significant (P<0.01). Conclusions miR-126 could inhibit apoptosis of myocardial cells in rats with AMI, which related to regulation of expression of cell apoptotic related protein.