Abstract: AIM：To investigate the chemical constituents of the whole plant of Ornithogalum caudatum Ait. METHODS: Various chromatographic techniques were used to separate the chemical constituents. ESIMS, IR, ¹HNMR, ¹³CNMR, DEPT, 1H-1H COSY, ¹H-¹³C COSY, HMBC and NOESY were used to determine the structure of the isolated constituents. RESULTS: Three compounds were isolated from the whole plant of Ornithogalum caudatum Ait. They were identified as (25S,23S,24S) spirosta-Δ⁵-ene-1β,3β,23,24-tetral-1-O-α-L-rhamnopyranosyl(1→2)-［β-D-xylopyranosyl(1→3)］-α-L-arabinopyranoside(I); Hecogenin 3-O-［β-D-glucopyranosyl-(1→2)-［β-D-xylopyranosyl-(1→3)］-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside］(II) and β-sitosterol (III). CONCLUSION: Compound 1 is a new steroidal saponin and was given the name caudaside A. Compounds II and III were obtained from this plant for the first time.