Abstract: Objective: To investigate the effect of Aa-LPS and IL-10 on apoptosis of Alveolar macrophages in vitro .Methods:Alveolar macrophages(AM) were harvested from the bronchoalveolar lavage fluid(BALF).These cells were randomly divided into three groups: control group, Aa-LPS group and Aa-LPS +IL-10 group. The number of cells was 1×106/ml in each group. Then these cells were given Aa-LPS(1μg/ml),IL-10（0.1μg/ml）.After 24 hours,the cells were harvested to extract RNA. Finally, RT-PCR was used to detect the expression of gene bax,p53 and caspase-3.Results:The results showed that the expression of bax and caspase-3 in the Aa-LPS group were significantly higher than the control group（P<0.05）.The expression of p53 was not statistical significant compared with the control group（P>0.05）. IL-10 treatment significantly inhibited macrophagocyte apoptosis and suppressed the expression of bax,p53 and caspase-3（P<0.05）.Conclusions: Aa-LPS can promote alveolar macrophages apoptosis in vitro and IL-10 can suppress the effect of Aa-LPS. The mechanism seemed related to the mitochondria-dependent pathway.