Abstract: Objective: To study the clinical application value of spectral CT in evaluating cardiac function in patients with ischemic heart disease,so as to provide a novel and reliable imaging diagnostic system for cardiac function. Methods: 40 patients with ischemic heart disease were scanned with the high resolution density coronary CT angiography(HDCTA) and the gemstone spectral imaging(GSI) modes. In addition, all cases had the Cardiac MRI scan within a week. Obtained monochromatic images(40 ~ 140 ke V) and the iodine-based material-decomposition images from Spectral Analysis Software. The k value and the iodine concentration of the normal myocardial and ischemic myocardium were obtained respectively. Software automatically calculate the EDV, ESV, EF of left ventricular. The results were compared with MRI evaluation results. Results: The k value and the iodine concentration of normal myocardial were higher than the ischemic myocardium. Ischemic myocardium detected on Spectral CT showed the corresponding segment wall motion degree decreased in cine-MRI imaging. There were good correlation and consistency between the EDV, ESV, EF calculated by HDCTA and the results calculated by MRI. Conclusions: Dual Energy Spectral CT combined with cardiac function analysis software can quantitatively evaluate myocardial blood supply, effectively evaluate cardiac function in patients with ischemic heart disease.