Objective:The aim of the study was to determine the position of ligation and control infarct size in the establishing of a rat myocardial infarction model (MI). Methods:Experimental group models (n=58) were produced by the ligation of left anterior descending coronary artery in left ventricular peak point along a line connecting the insertion of the left auricular appendage with the apex of the heart. MI control group (n=38) was produced by using the conventional method. Triphenyltetrazolium chloride (TTC) staining was performed to compare infarct size (IS,%) in two groups,and electrocardiogram (ECG) and echocardiography changes were observed also. Results:ECG monitoring showed that the success rate of the experimental group was significantly higher than that of the control group (88.9% vs 65.5%,P< 0.05). Moreover,there were 40 rats had medium-size infarction among experimental group detected by TTC. In contrast,only 11 rats had medium-size infarction among control group. It did differ significantly among rats with medium MI (P < 0.01). Conclusion:Accurately identify anterior descending coronary artery ligation site could help control the myocardial infarct size and improve the success rate of establishing myocardial infarction model.