Objective To evaluate the relation between the myocardial pathological lesion and the outcome of cardiac resynchronization therapy ( CRT ) in patients with dilated cardiomyopathy ( DCM ) using 99mTc-methoxy-isobutylisonitrile (99mTc- MIBI) myocardial perfusion single photon emission tomography (SPECT) and JSF-fluoro-2-deoxy-D-glucose (18F-FDG) imaging. Methods Totally 13 cases of DCM patients with heart failure were successfully implanted with CRT device. SPECT imaging was performed 6-month before and after CRT. Left ventricular myocardial perfusion and metabolic changes were evaluated by semi- quantitative analysis method in all patients. Results Compared with preoperative left ventricular ischemia necrosis areas and mass percentage, significant decrease was observed postoperatively [(18.2%±12.7%) vs (31.8%±15.4%), P＜0.05; (22.3%±14.9%) vs (36.4%±14.3%), P＜0.05]. There was negative correlation between necrotic area mass percentage or total myocardial perfusion score before operation ( F value) and CRT response (r＝-0.578, P＜0.05; r＝-0.619, P＜0.05), and significant positive correlation of preoperative myocardial perfusion zero score（N0）with improved postoperative left ventricular systolic function (r＝-0.655, P＜0.05) or left ventricular reverse remodeling (r＝0.719, P＜0.05). Conclusion The greater the myocardial cell necrosis before CRT, the worse effects of CRT. CRT can improve the regional myocardial blood perfusion, increase myocardial cell metabolism and reduce the extent of myocardial necrosis.