Abstract: Chemical investigation of the stems of Fritillaria unibracteata P.K. Hsiao & K.C. Hsia resulted in the isolation of nine compounds, by means of silica gel column chromatography, and preparative HPLC. Based on spectroscopic and chemical evidence, these compounds were identified as: 27-hydroxychlorogenone (1), sieboldogenin (2), (3β, 25S)-spirost-5-ene-3,17,27-triol (3), laxogenin (4), tigogenone (5), cerevisterol (6), ergosterol peroxide (7), stigmaterol (8), and β-sitosterol (9). Compound 1 was a new compound, and compounds 2-9 were isolated from the stems of Fritillaria unibracteata for the first time. The inhibitory effects of compounds 1−9 on A549 cells were determined using the MTT method. The results show that compound 6 exhibits moderate inhibitory activity with an IC₅₀ value of (14.16 ± 1.11) μmol/L.