Abstract: OBJECTIVE To investigate the interventional effectiveness and the relevant mechanisms of paclitaxel liposome aerosol inhalation on bleomycin-induced pulmonary fibrosis(BPF) in rats. METHODS The male SD rats were randomly divided into 4 groups, the healthy control group, the pulmonary fibrosis model group, paclitaxel liposome aerosol inhalation group and paclitaxel liposome injection group. In addition to the healthy control group, the pulmonary fibrosis model of other three groups were established by bleomycin intra-tracheal injection. The paclitaxel liposome was administered to the inhalation group for aerosol inhalation every other day and injection group for caudal vein injection. The other groups were inhaled the same amount of normal saline every other day. All groups were observed the general condition and the pathological changes of their lung tissue. The fibrosis degree was determined by Ashcroft's scoring and alveolar septal thickening measurement. The expressions of ColⅠ,Ⅲ and TGF-β1 in lung tissue were measured by immunohistochemistry. RESULTS Compared with the model group, there were significant decrease in paclitaxel liposome aerosol inhalation group in pulmonary fibrosis Ashcroft's scoring(P<0.01), alveolar septal thickening measurement(P<0.01) and expression of the ColⅠ, Col Ⅲ and TGF-β1(P<0.01). CONCLUSION There are significant protection in BPF rats treated with paclitaxel liposome aerosol inhalation. The degee of alveolitis, alveolar damage and fibrosis can be lowered, thereby reducing its mortality. And the potential protection mechanism may be related to inhibition of ColⅠ, Col Ⅲ and TGF-β1 expression.