Objective：To investigate the effect and possible mechanism of flavone of Trollius chinensis Bunge on myocardial ischemia reperfusion injury（MI/RI） in rats. Methods：Fifty male SD rats were randomly divided into sham operation group，model group，posi－tive control Di’ao Xinxuekang group，nasturtium total flavonoids high and low dose groups（10 rats in each group）. One week before the surgery，different doses（50，100 mg/（kg?d）） were given to nasturtium total flavonoids high and low dose groups by intragastric administration，0.06 g/（kg?d）crude drug was given to Di’ao Xinxuekang group by intragastric administration and the same amount of physiological brine was given to the other two groups. The myocardial ischemia reperfusion injury model was established through oc－cluding the left anterior descending branch of coronary artery for 30 min and removing the ligation later to reperfuse for 120 min in vivo. The changes of ST segment on ECG during ischemia and reperfusion was observed. The activity of superoxide dismutase（SOD），glutathion peroxidase（GSH-Px） and the contents of malondialdehyde（MDA），lactate dehydrogenase（LDH），creatine kinas（CK） in serum were detected. The infarction area was determined by TTC staining and the myocardial apoptosis was determined by TUNEL method. Results：Levels of serum MDA，CK，LDH were decreased，content of SOD was improved，activity GSH-Px was enhanced，and infarction area and myocardial apoptosis rate were effectively reduced in nasturtium total flavonoids high dose group（CK：945.2±94.6；LDH：978.8±37.5；MDA：5.75±1.22；SOD：107.71±10.95；GSH-Px：1.62±0.45；infarction area：22.18±1.99） than in control group（P＜0.01）. Conclusion：The flavone of Trollius chinensis Bunge could protect myocardium from MI/R injury and the mechanism may be associated with scavenging oxygen free radicals，reducing lipid peroxidation，inhibiting myocardial apoptosis and reducing the leak out of myocardial enzymes.