In the present study, we found that exosomes released by BMSCs successfully prevented alveolar macrophage injury and miR-384-5p in BMSC derived-exosomes played a pivotal role in relieving autophagy stress of alveolar macrophages by targeting Beclin-1, leading to protect LPS-induced ALI in vitro and in vivo. This evidence concerns the gene BECN1 and acute respiratory distress syndrome.