Objective：To observe the effects and mechanism of dexamethasone intervention on variations of tumor necrosis factor-α（TNF-α）、interleukin-8（IL-8） and IL-10 in serum of rabbits with acute respiratory distress syndrome（ARDS） induced by oleic acid at different time points. Methods：Totally 40 rabbits were randomly divided into normal control group（n=8）， ARDS group（n=8） and dexamethasone-treated group（n=24）. Animal model of ARDS was established by intravenous injection of oleic acid to rabbits’veins through ear margin. Dexamethasone-treated group was subdivided into three groups（n=8） by injecting dexamethasone at differ－ent time points（instantly，1，2 h）. Levels of TNF-α，IL-8 and IL-10 in serum were measured using radioimmunoassay and enzyme linked immunosorbeng assay（ELISA）. Results：Levels of TNF-α and IL-8 in serum were significantly higher in ARDS group than in normal control group（P<0.01）. Level of IL-10 in serum was significantly lower in ARDS group than in normal control group（P<0.01）. After dexamethasone treatment，levels of TNF-α and IL-8 in serum were lowered while level of IL-10 in serum was increased. Levels of TNF-α，IL-8 and IL-10 in serum were statistically different between dexamethasone-treated group and ARDS group（P<0.01）. Differ－ent variations of TNF-α，IL-8 and IL-10 levels in serum were observed when dexamethasone was given at different time points. Conclusions：TNF-α，IL-8 and IL-10 may play an important role in the inflammatory process of oleic acid ARDS in rabbits. Dexam－ethasone may relieve lung injuries by intervening the secretion process of TNF-α，IL-8 and IL-10. At the same time，the possible re－lationships may exist between the progression of inflammation and the intervention time of dexamethasone.