The experiment was designed to study the condition of rabbit myocardium after 10,000-Volt high tension electricity injury by using light and electron microscopes. Early change in myocardium was detected and it took a dynamic development. Also, the enzymogram of myocardium was found to be altered parallel with the pathological alteration, apart from significant changes showed in electrocardiograms. The result of the study demonstrated that organic injury occurred in myocardium after high tension electricity injury.