To observe the protection effect of Pingxianningfei Granule in rats with Bleomycin-induced pulmonary fibrosis. Methods:Sixty male SD rats were randomly divided into a control group， a model group(MG)， a high-dose Pingxianningfei Granule group(HG) and a low-dose Pingxianningfei Granule group(LG)， 15 in each. Model rats with Pulmonary Fibrosis were induced by injecting bleomycin into trachea. Respectively， 7， 14， 28 days after successfully medication， the rats were sacrificed， 5 in each group. Taking the lung， and analysis in histopathology. And the expression of transforming growth factor-β1(TGF-β1)， typeⅠand type Ⅲ Collagen in lung tissue was assayed by immunohistochemistry. Results:Infiltration of inflammatory cells were obvious in lung tissue of MG and the fibrous connective tissue proliferated. The pathologic changes of lung in HG and LG at 14， 28 days were milder than those in MG. The expression of TGF-β1， typeⅠand type Ⅲ Collagen in MG at 7， 14， 28 days was much higher than that of the control group， with statistical significance (P<0.01). Compared with the MG， the expression of TGF-β1， typeⅠand type Ⅲ Collagen of the lung in HG and LG was decreased， which showed significant difference (P<0.05， 0.01).Conclusion:Pingxianningfei Granule can effectively reduce the formation of pulmonary fibrosis and inhibit the expression of TGF-β1， typeⅠand type Ⅲ Collagen in lung tissue.