Exosomes, as the key mediators of intercellular communication, are extracellular vesicles derived from intracellular sources. They play various physiological roles in apoptosis regulation, immune responses, inflammation and other processes via their containing proteins and genetic materials, such as microRNAs. Stem cell therapy shows unique advantages in the repairing of myocardial cell injury. Evidence indicates that mesenchymal stem cell (MSC)-derived exosomes improve the viability of myocardial cells after ischemia/reperfusion injury, which suggests that the beneficial effects of the stem cells in the recovery may be associated with their secretion of exosomes. Therefore, exosome therapy might be a new direction for cell-free therapy strategy in myocardial repair. In this review, we summarized the roles of stem cell-derived exosomes in the repair of myocardial injury.