Objective To investigate the effect of extracellular vesicles (EVs) derived from mesenchymal stem cells (MSC) on neutrophil extracellular traps (NETs) in sepsis induced acute lung injury (ALI) and mechanism associated. Methods The model of sepsis induced acute lung injury was constructed by cecal ligation and puncture (CLP). Wild type mice were divided randomly into sham groups, CLP groups and CLP+MSC-EVs groups(n=6). MSC-EVs (200μg/each) were administered to mice through tail veins 1 hour before CLP surgery. Hematoxylin-Eosin (H-E) staining was used to assess the inflammation levels and condition of lung injury among groups, and immunofluorescence (IF) was conducted to compare the generation levels of NETs. Neutrophils were separated from blood and constituted control groups, PMA groups and PMA+MSC-EVs groups. Immunofluorescence staining was and ROS staining were performed separately to compare the production of NETs and the level of ROS production. Results Compared with sham groups, inflammatory cells infiltration and alveolar wall thickening were more pronounced in lung tissue of mice in CLP groups , whereas reduced in CLP+MSC-EVs groups. In addition, there was an increasingly release of NETs in CLP groups compared to sham groups, and a relatively decrease in the level of NETs in CLP+MSC-EVs groups(P0.05). In vitro, NETs formation was significantly increased in PMA groups and declined in PMA+MSC-EVs groups compared with control groups(P0.05). The level of ROS generation was significantly higher in the PMA group versus control groups, while it decreased noticeably in PMA+MSC-EVs groups. Conclusion Extracellular vesicles derived from mesenchymal stem cells could inhibit the formation of NETs via ROS and thus alleviate sepsis induced acute lung injury.