Reperfusion therapy has significantly reduced the mortality of patients with acute ST-segment elevation myocardial infarction (STEMI), but the associated heart failure mortality is on a rise. It is important to seek novel cardioprotective therapies to improve clinical outcomes. Cardiac magnetic resonance (CMR) is an important imaging modality for assessing the efficacy of the novel therapies and the prognosis of the patients. T1 mapping and T2 mapping have provided new insights into the pathophysiology underlying myocardial edema, microvascular obstruction, intramyocardial hemorrhage, and the remote myocardial interstitial space after reperfused STEMI. This review sums up the recent advances on the application of the CMR in reperfused STEMI.