Abstract: This paper is to introduce Han Shuren's clinical experience of treating pulmonary interstitial fibrosis with Buyang Huanwu Decoction. Han believes the pathogenesis of this disease is the qi and blood deficiency， especially in lung and kidney and he adopts nourishing qi and tonifying kidney as well as activating blood circulation to remove blood stasis as his main treatment principle. He also modifies Buyang Huanwu Decoction according to different situations of the patients with different ages and disease courses in clinic.