ST injury vector displayed in the compass was proposed to visualize the location and extent of myocardial ischemia. Analysis of ST deviations from the standard 12lead ECG allows for estimation a ST injury vector. The direction of this vector can be used to localize ischemia and the magnitude of the vector correlated with the extent of ischemia. Thirtytwo patients with myocardial ischemia were detected by the ST injury vector method. The result was compared with electrocardiogram, Kappa value was 0.903 6, sensitivity 96.2%, specificity 100% and accuracy 96.9%, positive rate of 81.3%,P>0.1; And compared with the coronary angiography, Kappa value was 0.7949, sensitivity 96.2%, specificity 83.3% and accuracy 93.8%, positive rate of 81.2%, P>0.1. It proved that there are high consistency and no significant difference between ST injury vector and electrocardiography and coronary angiography, and the accuracy is high. ST injury vector is valuable in the field of myocardial ischemia.