Abstract: OBJECTIVE To study the effect of Yangxin2 Fang on the myocardial energy metabolism in rats with chronic heart failure（CHF）， and to explore the mechanism of Yangxin2 Fang for the treatment of CHF. METHODS 45 male clean grade SD rats were divided into two groups， normal group（group A，n=6） and CHF group（n=39）.The CHF group was injected hypodermic with ISO for 28 consecutive days. After the model was successfully established in CHF， the survival rats were randomly divided into three groups: model group （group B）， Carvedilol group （group C）and Yangxin2 Fang group（group D）.Group C and group D were received gastric gavage of Carvedilol and Yangxin2 Fang respectively. Group A and group B were received gastric gavage of distilled water. After 28 days of dosing， the levels of myocardial adenosine triphosphate （ATP）and mitochondrial membrane potential （MMP） were tested. RESULTS ①the change of ATP level: Compared with the group A， the level of myocardial ATP was decreased in group B（P＜0.05）; Compared with the group B and C， the level of myocardial ATP was increased in group D（P＜0.01）.Compared with group C， the level of myocardial ATP was increased in group D（P＜0.01）. ②the change of MMP levels： Compared with group A， the levels of MMP was decreased in group B（P＜0.01） Compared with the group B， the levels of myocardial MMP were increased in group C and D.（P＜0.01）. CONCLUSION Yangxin2 Fang could increase the levels of myocardial ATP and MMP to improve myocardial energy metabolism， which might be one of the functionary mechanism of Yangxin2 Fang to treat CHF.