Three new lanostane-type triterpenes, inonotusanes A-C (1-3), and a new naturally occurring one, 3β-hydroxy-25,26,27-trinorlanosta-8,22E-dien-24-oic acid (4), together with sixteen known triterpenoids (5-20), including 13 lanostane derivatives, 2 lupanes and 1 oleanane-type triterpene were isolated from the sclerotia of Inonotus obliquus. Their structures were elucidated by 1D and 2D NMR spectroscopy and HRMS. Compounds 6, 8, 18 and 20 exhibited strong cytotoxicity against A549 tumor cell lines, with IC50 values of 2.34, 1.63, 8.39 and 5.39μM, respectively. Seven compounds (3, 9, 10, 12, 18-20) exhibited moderate cytotoxicity against A549, HT29, Hela or L1210 tumor cell lines.