〔Abstract〕 Objective To investigate the effect of superoxide dismutase(SOD) mimetic 4-Hydroxy-TEMPO(Tempol) on aortic vasodilation function in mice exposed to intermittent hypoxia. Methods Male C57 mice were randomly divided into normal oxygen(Control) group, intermittent hypoxia(IH) and IH+Tempol group. The mice in IH and IH+Tempol group were exposed to 4-weeks intermittent hypoxia, 8 h daily. In IH+Tempol treatment group, the mice were given Tempol(100 mg/kg) each day by the oral administration in the last week of intermittent hypoxia. The isolated thoracic aorta reactivity was studied using wire myography, the content of reactive oxygen species(ROS) was detected by dihydroethidium(DHE) staining, the concentration of nitric oxide(NO) was measured by ELISA kits. Results Compared with Control group, the endothelium-dependent vasodilation of thoracic aorta induced by acetylcholine(ACh) significantly decreased and cardiac hypertrophy, the level of aortic ROS significantly increased, the concentration of aortic NO was significantly reduced in the IH group mice. Treatment with Tempol could significantly improve the aortic endothelium-dependent vasodilation dysfunction and cardiac hypertrophy, and significantly inhibited the increase of ROS and decrease of NO in the thoracic aorta induced by intermittent hypoxia. Conclusion Tempol can improve intermittent hypoxia induced-cardiovascular dysfunction in mice by reducing ROS and increasing the bioavailability of NO.