Objective To explore the potential protective effect in vivo of Edaravone, a free radical scavenger on model of acute lung injury in rats with sepsis. Methods Twenty-four male Wistar rats were randomly divided into three groups, ie. a control group( NS group) , a model group( LPS group) , a Edaravone treatment group( ED group) . ALI was induced by injecting LPS intravenously( 10 mg/ kg) in the LPS group and the ED group. Meanwhile the ED group was intravenously injected with Edaravone( 3 mg/ kg) . The NS group was injected with normal saline as control. The lung tissue samples were collected at 6 h after intravenous injection. The wet / dry ( W/D) weight ratio of lung tissue was measured. The levels of myeloperoxidase ( MPO) , malondialdehyde ( MDA ) and superoxide dismutase ( SOD) in lung tissue homogenate were assayed. The pathological changes and expression of nuclear factor-kappa B( NF-κB) in lung tissue were also studied. Results Compared with the NS group, The W/D, pathological scores, NF-κB expression, MPO and MDA levels in the LPS group were significantly higher( all P lt; 0. 01) , and the level of SOD was apparently lower( P lt; 0. 01) . The W/D, pathological scores, NF-κB expression, MPO and MDA levels in the ED group were significantly lower than those in the LPS group( all P lt; 0. 01) and higher than those in the NS group( all P lt; 0. 01) . And the level of SOD in lung tissue of the ED group was higher than that in the LPS group and lower than that in the NS group ( P lt; 0. 01) . Conclusions Edaravone has protective effect on ALI rat model. The mechanismmay be related to its ability of clearing the reactive oxygen species, inhibiting the activation of the signal pathway of NF-κB and inflammatory cascade.