Abstract: Objective To investigate the different time of hydrogen sulfide inhalation in inhibiting oxidative stress of lung injury in rats. Methods Eighteen male SD rats were randomly allocated into control group, H₂S inhalation 3 h and H₂S inhalation 6 h group, 6 in each group. There were no H₂S inhalation in the control group, while the concentration of glutathione (GSH) in bronchoalveolar lavage fluid (BALF) and the γ-GCS in homogenized lung tissue of rats in the H₂S inhalation 3 h, 6 h groups were observed by ELISA assay, the immunohistochemically was applied to detect the relative expression of NF-κBp65 and Nrf2 with Image Pro Plus 6.0 software, and the method of fluorescence quantitative PCR were used to detect the expression of γ-GCSmRNA in homogenized lung tissue of rats. Results Compared with the control group, the GSH index decreased, and the concentration of γ-GCSmRNA and the expression of Nrf2 in the homogenized lung tissue of rats in the 6 h group significantly elevated, while those indexes in the H₂S 3 h group did not change significantly. Conclusion Low inhalation of hydrogen sulfide for 3 hours shows no significant effects on the oxidative stress in the lung tissue of rats, while 80 ppm inhalation of hydrogen sulfide for 6 hours can potentially induce oxidative stress and cause damage to lung tissue.