Objective To observe the influence on morphology and collagen of Angelica Sinensis on bleomycin-induced pulmonary fibrosis in rats and to explore its pathogenesis.Methods Thirty-six SD rats in good conditions were divided into three groups at random: control group,model group and Angelica Sinensis group.On experimental day(day 0),the rats were intratracheally instilled with bleomycin,and then treated with Angelica Sinensis 150mg·kg -1 ·d -1 by intraperitoneal injection.On the 7th and 28th day,six rats of each group were killed and the lungs were harvested for histopathological examination and blood was for determinations of collageni.Results Angelica Sinensis could obviously reduced alveolitis and fibrosis.The content of collagenⅠfrom blood in the 7th and 28th day in Angelica Sinensis group was decreased compared with model group satistically (P<0.01 and 0.05 respectively).Conclusion Angelica Sinensis may alleviate the process of pulmonary fibrosis of rats induced by bleomycin and has protective effect on rats with pulmonary fibrosis.