Objective:To establish a neonatal rat model of acute lung injury(ALI)induced by intraperitoneal administration of various doses of lipopolysaccharide(LPS)and investigate the role of receptor for advanced glycation end－products(RAGE)in ALI. Methods:Thirty newborn rats were randomly divided into five groups(six in each group)according to the different doses of LPS(0.3,1,3 and 9 mg/kg)and saline. All the rats were sacrificed and observed 24 h later. Levels of tumor necrosis factor alpha(TNF－α)and soluble RAGE(sRAGE)in the plasma and bronchoalveolar lavage fluid(BALF)were detected by enzyme－linked immunosorbant assay(ELISA). RAGE mRNA levels in tissue homogenates were detected by RT－PCR and RAGE protein levels by Western blot. The pathological assessment of lung tissues was performed by HE staining. Results:The LPS 9mg/kg group was excluded due to its high mortality(83.3%). When compared to the control group,the levels of TNF－α,the expression of RAGE protein and RAGE mRNA,and the lung damage scores in the other four groups were increased. All these parameters increased in a dose－dependent manner in the LPS groups,while the levels of sRAGE in BALF decreased. Conclusion:LPS intraperitoneal injection can induce ALI in neonatal rats. LPS dosage of 3 mg/kg may be the optimal dose for ALI model in neonatal rats. RAGE can be used as a sensitive indicator of ALI.