Objective To explore a feasible method and time for establishment of acute myocardial infarction(AMI) in rats. Method Experiments were performed in 38 Wistar rats with respirator. After anesthetized with phenobarbital sodium, a left lateral thoracotomy was performed through 3-4 intercostals region. The left anterior descending coronary artery (LAD) was ligated by 8-0 sutures to shut the blood supply of myocardium controlled by LAD. Acute myocardial infarction (AMI) created by this technique were confirmed by continuous electrocardiographic monitoring, pathologic section and echocardiographic study. Results After ligation of LAD, ECG displayed ST elevated continuously and pathologic Q wave. Pathologic section suggested myofibers chaotically arranged, myofilament ruptured or lysed, nuclei pyknosis and fragmentation, interstitial hyperemia and edema, and infiltration of inflammatory cells. Meanwhile, echocardiographic study showed ejection fraction didn't descend markedly after ligation of LAD. Conclusion AMI could be created by surgical ligation of LAD,and the animal model would be conducive to the basic study on AMI.