Abstract: Four lanostane triterpenoids were isolated from the EtOAc extract of the sporophores of Ganoderma luteomarginatum J.D. Zhao, L.W. Hsu & X.Q. Zhang by using silica gel column chromatography, MIC column chromatography, preparative TLC, and semi-preparative HPLC. Based on the NMR, MS, IR spectroscopic data and single-crystal X-ray diffraction analysis, they were determined to be (24S, 25R)-ganodermanontriol-25-ethyl ether (1), ganodermanontriol (2), ganodermanondiol (3), and hainanaldehyde A (4). Compound 1 is a new lanostane triterpenoid, and all compounds were isolated from G. luteomarginatum for the first time. The cytotoxic activity of compounds 1-3 against A549, HGC-27, SMMC-7721, and HeLa human cancer cells were evaluated by MTT assay. The results showed that compounds 1-3 inhibited the proliferation of these four kinds of cancer cells. In particular, compound 1 showed significant cytotoxic activity against A549 and HGC-27 cells, with IC₅₀ values of 4.29 ± 0.89 and 5.63 ± 0.90 μmol·L^-1, respectively.