Objective: This study was aimed at investigating the expression and therapeutic potential of circRNAs from adiposederived stem cell (ADSC) exosomes (ADSC-Exos) for cardiomyocyte injury. Methods: We screened differentially expressed circRNAs between ADSCs and ADSC-Exos with a circRNA microarray. A differential circRNA-0008302 siRNA plasmid was constructed to obtain ADSC-Exo and ADSC Exommucirc-0008302 siRNA, respectively; subsequently, M6200 cells were divided into a control group, hydrogen peroxide (H2O2) induced group, H2O2 + ADSC-Exo group, and H2O2 + ADSC-Exommu-circ-0008302 siRNA group, and cell viability was evaluated. Apoptosis and intracellular reactive oxygen species were measured. The expression levels of miR-466i-5p were evaluated, and western blotting was performed to detect the expression of methionine sulfoxide reductase A Results: Expression of circ-0008302 was significantly more elevated in the ADSC-Exo group than the ADSCs group. The treatment protected cardiomyocytes against H2O2-induced oxidative injury. Mechanistically, circ-0008302 downregulated miR-466i-5p levels, thus promoting expression of the miR-466i-5p target gene MsrA in cardiomyocytes. Conclusions: ADSC-Exos play protective roles in mitigating myocardial injury by delivering circ-0008302 to cardiomyocytes; this circRNA targets miR-466i-5p and subsequently enhances the expression of MsrA.