Objective To study the value of coronary CT angiography (CCTA) and dynamic electrocardiogram (DCG) in the diagnosis of myocardial ischemia in coronary heart disease (CHD). Methods 300 cases of suspected CHD patients were given CCTA and DCG detection, and the results of radionuclide myocardial perfusion imaging (MPI) were taken as a gold standard to assess the diagnostic value of CCTA combined with DCG. Results CHD myocardial ischemic rate in MPI detection was 61.67% and there were 204 myocardial perfusion abnormal areas, including 29 fixed perfusion defect areas and 175 reversible perfusion reduction areas. Myocardial ischemic rate in CCTA diagnosis was 63.67% and there were 224 systolic myocardial perfusion abnormal areas, including 27 fixed perfusion defect areas, 66 partially reversible perfusion filling areas and 131 reversible perfusion filling areas. Myocardial ischemic rate in DCG diagnosis was 52.67%, and 11 cases upward sloping ST segment depression, 33 cases downward sloping depression and 114 cases horizontal depression were shown by DCG diagnosis. Myocardial ischemia rate in CCTA combined with DCG diagnosis was 66%. The rates of sensitivity, specificity, positive predictive value, accuracy, Kappa value were 83.78%, 68.70%, 81.15%, 78%, 53% in CCTA respectively and were 71.35%, 77.39%, 83.54%, 62.68%, 73.67%, 46.68% in DCG respectively, and were 94.59%, 80%, 88.38%, 90.20%,89%, 79.23% in CCTA combined DCG. Conclusion Both CCTA and DCG have good diagnostic efficacy in the diagnosis of myocardial ischemia in coronary heart disease, but CCTA combined with DCG diagnosis is better for recognition and can improve the diagnostic detection rate.