OBJECTIVE：To compare the protective effect of atomization inhalation and intraperitoneal injection of edaravone on acute lung injury in smoke inhalation lung injury model rats. METHODS ：Thirty male SD rats were divided into normal control group（group A ），injury group （group B ），intraperitoneal injection group （group C ），low-dose aerosol inhalation group （group D），high-dose aerosol inhalation group （group E ）according to random numble table ，with 6 rats in each group. Group B-E were placed in smoke generator containing pine sawdust to induce smoke inhalation lung injury model. In group A ，the operation was the same as above except that the pine sawdust was not placed. Thirty minutes after modeling ，group C were injected intraperitoneally with edaravone 18 mg/kg（every 70 min，4 times in total ）. Group D and E inhaled edaravone 9，1.8 mg/kg（every 60 min，lasting for 10 min each time ，4 times in total ）. The rats were treated by no means in group A and group B. Six hours after last medication，arterial blood gas analysis was performed ，and the lung wet to dry ratio （W/D）and water content of lung tissue were calculated. The levels of TNF-α，IL-6 and IL- 10 in serum were detected by double antibody ELISA. The contents of MDA ，MPO， SOD and Caspase- 3 in lung tissue were determined by ELISA and other methods. HE staining was used to observe the pathological changes of lung tissue. The apoptotic rate of cells in lung tissue were determined by TUNEL assay. RESULTS ：No abnormality was found in lung tissue of group A ；in group B ，hemorrhage and edema were found in lung tissue ，alveolar structure was difficult to identify，and inflammatory cells and red blood cell infiltration were seen. Above symptoms of rats in group C-E were improved to different extent. Compared with group A ，PaO2/FiO2 and SOD content of lung tissue were decreased significantly in other groups （P＜0.05）；water content of lung tissue ，W/D，serum contents of TNF-α，IL-6 and IL- 10，the contents of MDA ，MPO and Caspase-3 in lung tissue ，apoptotic rate were increased significantly （P＜0.05）. Compared with group B ，PaO2/FiO2 and serum contents of IL- 10 were increased significantly in administration groups （P＜0.05）；water content of lung tissue ，W/D，serum contents of TNF-α and IL-6，the contents of MDA ，MPO and Caspase- 3 in lung tissue ，apoptotic rate were significantly decreased，in dose-dependent manner （P＜0.05）. CONCLUSIONS ：Edaravone has a certain protective effect on smoke inhalation lung injury model rat. It can reduce the production and release of inflammatory mediators and/or cytokines ，reduce the peroxide damage and inhibit cell apoptosis in a dose-dependent manner. The effect of atomization inhalation is more obvious than that of intraperitoneal injection.