Abstract: To explore the protective mechanisms of a novel molybdenum disulfide (MoS₂) nanozyme in alleviating inflammation-related endothelial cell injury by regulating mitochondrial dynamic, flower like-MoS₂ nanosheets were prepared by hydrothermal method, and its antioxidant enzyme-mimic activities were assessed via electron spin resonance (ESR) spectroscopy. It was shown that MoS₂ nanosheets had strong scavenging ability for hydroxyl radical (·OH) and singlet reactive oxygen species (¹O₂) in a dose-dependent manner. Using an in vitro lipopolysaccharide (LPS)-induced vascular endothelial cell injury model, the protective roles of MoS₂ nanozyme on cytotoxicity and apoptosis of endothelial cells were examined by MTT and Annexin V-FITC/PI assay, respectively. Mitochondrial fission/fusion of endothelial cell were observed by Mito-Tracker green probe. Reactive oxygen species (ROS) probe DCFH-DA and superoxide anion probe DHE were used to detect the level of oxidative stress in vitro. Plasmid GFP-LC3 transfection using colocalization analysis was applied to assess the autophagy of endothelial cells. The results showed that MoS₂ nanozyme could significantly reduce the cytotoxicity and apoptosis of endothelial cells stimulated by LPS, and prevent the impairment mitochondrial dynamics of endothelial cells, thus maintaining mitochondrial dynamics. In addition, MoS₂ nanozyme was also shown to alleviate LPS-mediated endothelial mitochondrial autophagy, thus protecting endothelial cells from inflammatory stress. These results established that MoS₂ nanozyme protected endothelial cells injury from inflammatory stress by regulating mitochondrial dynamics and mitochondrial autophagy of endothelial cells, which is expected to expand the use of MoS₂ nanozyme in the prevention and treatment of inflammation-related vascular endothelial diseases.