Objective To determine the effect of acute myocardial ischemia on hemodynamic status and electrocardiogram (ECG) J-point displacement (⊿J) in rats and the intervention effect of Tongmai Ciwujia Capsule [a capsule mainly containing stem-leaf total flavonoid of Ciwujia, (Acanthopanax senticosus)] in the process. Methods Thirty rats with normal ECG were randomly divided into 3 groups according to the range of body mass, ie, sham operation group, model group and intervention group. The rats of the intervention group were orally administrated with Ciwujia suspension of 3.5ml/kg every day while the rats in the other 2 groups were given equal volume of normal saline for 14 consecutive days. Left anterior descending coronary artery (LAD) was ligated to establish the model of acute myocardial ischemia. The catheter of pressure transducer was put into the left ventricle to detect the changes of pressure in 15min after ligation. ECG was also monitored and ⊿J was recorded in 0.5, 1, 2, 4 and 6h after ligation to evaluate the intervention of Ciwujia Capsule. Results Compared with sham operation group, left ventricular end-diastolic pressure (LVEDP) and ECG ⊿J at 0.5, 1, 2, 4 and 6h after ligation were significantly increased (P＜0.05), while left ventricular systolic peak pressure (LVSP) and maximum rate of pressure change (±dp/dtmax) were decreased markedly (P＜0.05) in model group. Compared with model group, Ciwujia intervention resulted in significantly decreased LVEDP and ⊿J at the above time points except in 0.5 and 6 h after ligation (P＜0.05), and markedly increased LVSP and ±dp/dtmax (P＜0.05). Conclusion Ligation of LAD results in obviously impaired myocardial diastolic and systolic function and obvious J-point displacement ECG. Tongmai Ciwujia Capsule could effectively alleviate the impact of acute myocardial ischemia on ECG of rats.