Objective:To discuss two different ways of staining methods in evaluating myocardial ischemia-reperfusion injury. Methods:Anesthetized SD rats were subjected to myocardial ischemia reperfusion injury(ischemia 30 mins/reperfusion 6 hrs). Hemodynamic parameters were measured upon the completion of reperfusion in rats. The hearts were stained with TTC or Evans blue-TTC double-staining,separately,to determine the extent of myocardial damage. All the rats used in the experiment had the same LV morphology and the similar function. Results:The Evans blue-TTC double-staining method can measure the ratio of infarct areas-to-total left ventricular areas(I/R ratio),While the TTC staining can only measure the ratio of infarct areas-to-risk areas(I/T ratio). Compared with the I/T ratio,the I/R ratio has higher relevance with the cardiac function. Conclusion:The Evans blue-TTC double-staining method can determine the degree of myocardial damage induced by the ischemia-reperfusion injury more objectively and accurately than the TTC staining method.