Objective Comprehensive evaluation of an improved method of inducing myocardial ischemia- reperfusion injury (MIRI) in rats. Methods Forty-five SD rats were randomly divided into three groups: fast operation group, conventional thoracotomy group, and improved group (n = 15 in each group). Rat models of MIRI were established by rapid operation, routine thoracotomy, and the improved method , respectively. TTC+Evans blue staining was used to observe rat hearts. The degree of injury was analyzed and compared regarding three aspects: success rate of modeling, survival rate of rats, and myocardial injury. Results Compared with the fast operation group and conventional thoracotomy group, the success rate and survival rate with the improved method were improved, and the area and thickness of myocardial infarction were the same.Conclusions The improved method of MIRI modeling is feasible and can be popularized.