Cardiovascular diseases (CVD) are a significant cause of human health harm. In the past, stem cell therapy was reported to have functional defects, such as immune rejection, tumorigenicity, and infusion toxicity. Exosomes are extracellular vesicles with lipid bilayer membrane structure, containing proteins, lipids, mRNA, miRNA, DNA, and other molecules, which can mediate various biological functions such as immune response, inflammatory response, cell migration, and differentiation intercellular communication. Exosomal miRNAs have outstanding advantages in disease diagnosis and curative effect prediction. Likewise, paracrine factors could also mediate the main therapeutic effect of mesenchymal stem cells. Research has shown that mesenchymal stem cell-derived micro-exosomes, which may come from stem cells, accumulate in the ischemic tissue and regulate cell proliferation, apoptosis, inflammation, and angiogenesis sites of myocardial injury after being transplanted. This review reviewed the molecular mechanisms of exosomes and internal microRNAs derived from mesenchymal stem cells in cardiac ischemic injury repair.