[Objective]To summarize the clinical experience of Professor YAN Jun in treating idiopathic pulmonary fibrosis(IPF)with the principle of"moistening with pungent herbs".[Methods]Through attending the outpatient work and collating the relevant medical records,Professor YAN's understanding of the etiology and pathogenesis of IPF was analyzed,and the theoretical basis,the clinical medication experience of Professor YAN in treating IPF by using Bushen Yifei Xiaozheng Formula were explained and verified with one clinical case.[Results]According to Professor YAN,the pathogenesis of IPF is deficiency of lung and kidney,deficiency of Yin and fluids,loss of nourishment of the lung lobes,resulting in lung impotence;the lung lobes are weak,dysfunctional in declaring and descending,leading to stagnation of Qi movement,inable to move water,phlegm and drink stopping,Qi stagnation and blood stasis,internal accumulation of phlegm and blood stasis,resulting in paralytic obstruction of the lung channels and the occurrence of lung paralysis,and the lung paralysis for a long period of time results in lung dysfunction and the aggravation of impotence.Pungent medicine can disperse and move,enter the lung,promote through the Xuanfu,regulate Qi,disperse blood stasis,expel phlegm and accumulated nodules,and is consistent with the treatment rule of IPF.Based on the principle of"moistening with pungent herbs",Professor YAN creates Bushen Yifei Xiaozheng Formula.The cited IPF patient was deficiency of the lungs and kidneys,phlegm and blood stasis syndrome,the rule of tonifying the lungs and benefiting the kidneys,eliminating phlegm and removing blood stasis was applied,using Bushen Yifei Xiaozheng Formula,which had a good therapeutic effect in clinic.[Conclusion]The efficacy of using"moistening with pungent herbs"in the treatment of IPF is remarkable,and it has a good significance for clinical guidance,which is worth studying and passing on.