The invention belongs to the technical field of medicines, and particularly relates to a medicine for treating pulmonary interstitial fibrosis, and a preparation method of the medicine. The medicine for treating pulmonary interstitial fibrosis comprises the following components: astragalus mongholicus, codonopsis pilosula, coastal glehnia root, salvia miltiorrhiza, angelica sinensis, ligusticum wallichii, honeysuckle, fructus forsythiae, scutellaria baicalensis, rhizoma pinelliae preparata, bulbus fritillariae cirrhosae and liquorice. According to the medicine, the astragalus mongholicus and codonopsis pilosula have the effects of tonifying Qi of lung and spleen; the coastal glehnia root has the effect of tonifying Yin of lung and spleen; the salvia miltiorrhiza, angelica sinensis, ligusticum wallichii, honeysuckle, fructus forsythiae, scutellaria baicalensis are used as the supplementary medicines and have the effects of clearing away stasis and resolving phlegm; the rhizoma pinelliae preparata and bulbus fritillariae cirrhosae are respective in moisture state and wet state and are assistant for resolving phlegm; and the liquorice is used for blending other medicines; and all the medicines are blended to realize the effects of supplementing Qi and nourishing Yin, and clearing away stasis and resolving phlegm, and as a result, the Qi can be recovered, the phlegm and stagnant heat can be cleared away, the Qi of the lung and spleen can be tonified by sweat evaporating and turbid descending, the fluid in human body can be smoothly balanced, and the functions can be recovered. The medicine has the functions of supplementing Qi and nourishing Yin, and clearing away stasis and resolving phlegm, and is mainly used for treating breathe hard symptom, weak symptom, dyspnea and tachypnea symptom, coughing symptom and chest pain symptom in clinic.