Objective To optimize the method of establishing and evaluating rat models of myocardial infarction, and improve the reliability and stability of the model.Methods The left descending coronary artery in male SD rats was ligated to establish myocardial infarction model. Some important steps such as anesthesia, tracheal intubation, heat insulation, operation technique and postoperative care were improved during the modeling, and the effect of different anesthesia and different postperative days on myocardial infarction size was observed. Different staining methods were used to evaluate the infarction size in the rat myocardial infarction model. Results By comparing the anesthesia time, postoperative recovery and infarction size of each group during the process of myocardial infarction modeling, the sodium pentobarbital was shown to be more appropriate anesthetic. Different days after ligation had no significant effect on the modeling of myocardial infarction (P >0.05); but the myocardial ischemia area was significantly decreased with longer postoperative duration (P<0.01). 2,3,5-triphenyl tetrazolium chloride (TTC) and Evans blue double staining clearly visualized myocardial ischemia area and infarction area compared with TTC staining. Conclusions The optimized rat models of myocardial infarction in this study improve the animal welfare, and the establishing and evaluating method is more objective and accurate.