Pulmonary fibrosis is a common and irreversible pathological outcome of many chronic lung diseases. Yifei Sanjie prescription is an experiential prescription in treating pulmonary fibrosis. The prescription is authorized by professor Qingshen Li, a famous physician in traditional Chinese medicine in Yunnan Province. This paper analyzed and summarized its mechanisms in preventing and treating pulmonary fibrosis. Results suggested that, the active ingredients included the astragalus polysaccharides, total notoginseng saponins, curcumin, and curcumenol; which play important roles in immune regulation and anti-inflammation to alleviate pulmonary fibrosis by regulating PI3K/AKT signaling pathway, TGF-beta1/Smad signaling pathway, NF-kappa B signaling pathway, and MAPK signaling pathway.