Abstract: Objective:To clarify the protective effects of heme oxygenase in endotoxin-induced acute lung injury（ALI） in rabbits.Methods: Twenty four male New-Zealand rabbits were divided into three groups: control group A,endotoxin-treated group B and endotoxin plus hemin treated group C.ALI models of rabbits were replicated with intravascular endotoxin injection（700 μg/kg）.The partial presser of oxygen,malondialdehyde（MDA） content and superoxide dismutase（SOD） activity in blood serum were measured before experiment（0 h） and after experiment 0.5 h,1 h,2 h and 4 h.HO-1 protein（density mean） were measured in pulmonary tissue.Results: After infusion of endotoxin,in group B,it was observed that the partial presser of oxygen decreased to 7.287 kPa（＜8 kPa） at 0.5 h.The SOD activity in group B were obviously lower than those in group A（P＜0.01） and MOD were higher than those in group A（P＜0.01） at 2 h and 4 h in experiment.HO-1 protein in pulmonary tissue in group C were higher than those both in group A and group B（P＜0.01）.Conclusion: The increased expression of HO-1 in pulmonary tissue has some protective effects on ALI induced by endotoxin.