Disclosed is a new use of a compound as indicated in structural formula I in preparing medications for preventing and/or treating pulmonary fibrosis. The compound having the structure as indicated in structural formula 1 substantially reduces the inflammation of diseased lung tissue, lowers the concentration of fibrosis factors TGF-²l in diseased lung tissue, decreases the excessive deposition of collagen in diseased lung tissue, and has substantial prevention and treatment effectiveness against fibrosis.