Ｏｂｊｅｃｔｉｖｅ　To investigate the effect of high dose of ambroxol on lipolysaccharide（LPS）-induced acute lung injury（ALI） in rats.　Methods　Twenty-four male BALB/C rats were randomly divided into 3 groups（n＝8）： group A served as control group and received normal saline intracheally. Group B and group C received intracheal instillation of LPS（3 ml/kg）. At 6 h after LPS or saline instillation， ambroxol（100 mg/kg） were administered into the tail vein in group C， and normal saline were administered at the same volume in group A and group B. Another dose of amborxol or normal saline were administered 24 h later. At 48 h after LPS or saline instillation， lipoxin A4， tumor necrosis factor（TNF）-α， interleukin（IL）-10， total protein and polymorphonuclear cells count in bronchoalveolar lavage fluid， and wet/dry weight ratio and myeloperoxidase（MPO） in lung tissues were measured. The morphopathogical changes in lung of mice were observed by hematoxylin?蛳eosin（HE） staining.　Results　At 48 h after LPS or saline instillation， lipoxin A4［（332±19） ng/L］ and IL-10［（36±6） ng/L］ in bronchoalveolar lavage fluid in group C were higher than that of group B［（273±25），（9±3） ng/L］. Levels of TNF-α［（243±65） ng/L］， total protein［（0.328±0.037） mol/L］， and polymorphonuclear cells count［（39.99±14.41）×104/ml］ in group C were lower than that of group B［（391±105） ng/L，（0.444±0.283） mol/L，（137.94±28.98）×104/ml］. Wet/dry weight ratio（3.65±0.18） and MPO［（6.4±0.4） U/g］ in lung tissues in group C were lower than that of group B［（4.37±0.58），（137.9±29.0） U/g）］. Morphopathogical changes of lung tissues were attenuated significantly in group C more significantly than that of group B.　Conclusions　Large dose of ambroxol might have the therapeutic efficiacy on LPS-induced ALI in rats partly through promoting the resolution of inflammation.