To study the protective effect of Danshen Tongluo capsule on rat hearts in the myocardial infarction (MI) model. After being fed with high fat diets for one month, the SD rats were randomly divided into the sham group and the model group according to the left ventricular ejection fraction (EF). The MI model group was duplicated by ligating coronary artery and then divided into five groups: the model group, the positive control group (model + captopril), the small dose group (model + Danshen Tongluo), the medium dose group (model + Danshen Tongluo) and the high dose group (model + Danshen Tongluo). Four weeks later, changes in myocardium ultra-structure were observed by hemodynamics, cardiac ultrasound and electron microscope. The results showed: (1) All doses of Danshen Tongluo capsule could significantly reduce the left ventricular end diastolic pressure (LVEDP) (P <0.01), increase the maximum internal pressure of the left ventricle (+ dp/dtmax), and lower the drop rate of left ventricular pressure (- dp/dtmax), with statistical significances in medium and high dose groups; (2) The B ultrasound results showed increase in EF and left ventricular shortening fraction (FS) in all dose groups of Danshen Tongluo capsule; (3) The medium dose group showed significant decrease in myocardial infarction index (P <0.01) and injured and fractured myofilament and sarcomere of ischemic myocardium in myocardial ultra-structure; All of Danshen Tongluo capsule-treated groups revealed reduction in myocardial injury and myocardial infraction area. The study preliminarily proves that Danshen Tongluo capsule can improve hemodynamic function, and has a protective effect on myocardial ischemia.