Objective To evaluate the application of multi-slice spiral CT (MSCT) in evaluating myocardial activity in patients with myocardial infarction. Methods Sixtyeight patients with myocardial infarction admitted in our hospital from June 2013 and June 2015 were selected as the study subjects. Prospective first pass and delayed enhanced 64 slice MSCT and magnetic resonance (MR) myocardial perfusion imaging were performed in all patients. The results of MSCT in first pass phase and delayed phase were compared. MSCT and MRI first pass perfusion and delayed enhancement were comparatively analyzed. Results Of 68 patients in the study, 97.06% had delayed enhancement. The delayed enhancement in 32.35% was non transmural enhancement, transmural enhancement in 17.65%, mixed type in 44.12%, and no enhancement in 2.94%. Of all the patients, 61.76% had perfusion defect in the first pass phase and enhancement in delayed phase; 2.94% of the patients had first pass perfusion defect and enhancement in delayed phase. There was no significant correlation between the first pass phase and the delayed phase (P>0.05). There were a total of 997 myocardial segments in 68 patients, including 59 segments manifesting as perfusion defects in the two groups at the same time and 883 segments manifesting as non perfusion defects, and the coincidence rate was 94.48%. The consistency of MSCT and MRI in judging first pass perfusion was good. With MRI as the reference standard, both showed 680 segments without enhancement, 30 segments with non transmural enhancement and 105 segments with transmural enhancement. The coincidence rate was 81.75%, and the consistency of MSCT and MRI in judging myocardial activity was good but MSCT overestimated the range of infarction. Conclusion The consistency of MSCT and MRI in the evaluation of myocardial activity is good. MSCT can be used to detect myocardial activity.