A new caryolane sesquiterpene, 1β-methoxycaryol-9-one (1), along with eight known compounds (2-9), was isolated from the whole plant of Heteropappus altaicus. The structures were elucidated on the basis of comprehensive 1D- and 2D-NMR analysis and high-resolution mass spectrometry. The 13C-NMR data of compound 2 are reported for the first time.