Aim To investigate the protective effects of flavonoid crude extracts from Lonicerae Flos on acute myocardial ischemia in rats. Methods The rat model of acute myocardial ischemia (AMI) in oxidative damage was prepared by subcutaneous injection of isoproterenol hydrochloride. After intragastric administration for 7 days, the changes of rat left ventricular pressure and electrocardiogram were detected by dynamic electrocardiogram, the percentage of myocardial ischemia area was observed by nitroblue tetrazol(NBT) staining and the activity of protease or the amount of product in serum were detected by ELISA. Results The acute myocardial ischemia rats fed with honeysuckle flavonoids extract, the ST-segment and T wave in their electrocardiogram elevation by isoproterenol-induced were significantly alleviated, and the time of QT interval was shortened. The percentage of myocardial ischemia area was decreased.The heart rate, the left ventricular systolic pressure, diastolic and mean pressure were rebounded significantly. The serum malondialdehyde(MDA)content was reduced, the activity of protease was back to normal trend with reduction of creatine kinase(CK)and lacate dehydrogenase(LDH) and enhancement of superoxide dismutase(SOD). Conclusion This study shows that improvement effects of flavonoids crude extract from Lonicerae Flos were confirmed on acute myocardial ischemia caused by oxidative damage in rats.