Objective To verify the protective lung protection of non ⁃injurious double lung hypoxia pre⁃ conditioning in patients undergoing one⁃lung ventilation surgery. Methods Sixty adult patients undergoing elective thoracic surgery were randomly divided into group A（n = 30）and group O（n = 30）. Anesthesia was induced and maintained totally by intravenous target ⁃ controlled infusion，followed by mechanical ventilation after inserting a double⁃lumen bronchial tube. In group A，hypoxic preconditioning was performed：At towel laying，the respiratory circuit continuously switched off for three times，each time with mechanical ventilation off for 1 minute and on for 1 minute. Group O was as a control group. Vital signs，oxygenation index（OI），IL⁃6，TNF⁃ α，superoxide dismutase （SOD）were recorded and compared between the two groups before surgery，20 minutes after OLV，30 minutes after extubation and 6 hours after surgery. Results The patients in group A had significantly higher OI during OLV and after operation than group O（P < 0.01），and the incidence of hypoxemia in group A was significantly lower than that in group O. The levels of IL⁃6 and TNF⁃α in group A were significantly lower than those in group O after operation（P < 0.01），and the SOD was significantly higher than that in group O a well（P < 0.01）. Conclusion Non ⁃injurious double lung hypoxia preconditioning can improve oxygenation and reduce the level of inflammation expression and the incidence of pulmonary complications in patients undergoing one⁃lung ventilation surgery，play⁃ ing a positive role in lung protection.