Objective:To study the effects and mechanisms of acetyl-11-keto-β-boswellic acid ( AKBA) in myocardial ischemic model induced by isoproterenol hydrochloride ( ISO) in rats. Methods:The SD rats were randomly divided into the sham group, model group, AKBA low dose group and AKBA high dose group. Myocardial injury model was induced by subcutaneous injection of ISO (100 mg·kg-1 ) . The change of ST segment in ECG was observed. Creatine kinase ( CK-MB) , cardiac troponin I ( cTnI) , lactate dehydro-genase( LDH) , malondialdehyde( MDA) and superoxide dismutase( SOD) in the blood were detected by ELISA. The change of histo-logical tissue was determined by HE staining, and cell apoptosis was analyzed by TUNEL assay. Results: Serum CK-MB, cTnI and LDH were decreased significantly in AKBA high dose group when compared with those in the model group. Compared with that in the model group, MDA content was lowered and the SOD activity was increased in AKBA high dose group. Furthermore, AKBA high dose group improved the pathologic changes of myocardium. TUNEL assay revealed significant reduction of cardiomyocytes apoptosis in the hearts of the ischemic rats in AKBA high dose group. Conclusion:AKBA has excellent cardioprotective effect on myocardial ischemic induced by ISO and protection of myocardial cells from injury.