To study the preventive and protective effects of Jingfang Granules on lipopolysaccharide(LPS)-induced acute lung injury in mice，and to preliminarily explore the mechanism.Methods:Male C57BL/6 mice were randomly divided into control group，model group，and Jingfang Granules low-，medium-，and high-dose groups(1.25 g/kg，2.5 g/kg，and 5 g/kg，respectively)，10 in each group.Mice in each group were separately given normal saline of the same volume and Jingfang Granules of corresponding concentrations.After 6 d of administration，the model of acute lung injury was established by endotracheal infusion of LPS in model group and Jingfang Granules groups，while the control group received the same volume of normal saline by endotracheal infusion.The macroscopic morphological changes of lung tissues in each group were analyzed.HE staining was used to observe the pathological changes of lung tissues and the pathological score was given.Monocyte chemotactic protein 1(MCP-1)，interleukin-1β(IL-1β)，interleukin-6(IL-6) and tumor necrosis factor-α(TNF-α) in lung tissues were detected.Oxidative stress indicators such as myeloperoxidase(MPO)，inducible nitric oxide synthase(iNOS)，malondialdehyde(MDA)，superoxide dismutase(SOD)，and glutathione(GSH) were also detected.Results:Compared with the the conditions in control group，MCP-1，TNF-α，IL-1β，IL-6，MPO，iNOS and MDA in the lung tissues of mice in model group as well as the pathological score were increased(P<0.01)，with severe macroscopic morphological changes，and the activities of SOD and GSH were decreased(P<0.01).Compared with model group，Jingfang Granules groups had down-regulated MCP-1，TNF-α，IL-1β，IL-6，MPO，iNOS and MDA to different degrees(P<0.05)，and increased activities of SOD and GSH(P<0.05).The pathological score of lung tissues was lowered(P<0.01)，and the macroscopic morphology was improved.Conclusion:Jingfang Granules can inhibit LPS-induced acute lung injury to a certain extent and improve the macroscopic morphology and pathological changes of lung tissues.The mechanism may be related to inhibiting the inflammatory factors，reducing the oxidative stress，and enhancing the antioxidant capacity of the body.