From the ethyl acetate fraction of the fruiting body of Ganoderma lucidum, a new triterpenoid, ethyl 7β-hydroxy-4,4,14α-trimethyl-3,11,15-trioxo-5α-chol-8-en-24-oate (4), named ethyl lucidenates A, along with three known compounds, ganodermanondiol (1), lucidumol B (2) and methyl lucidenates A (3) were isolated by silica gel column, ODS column chromatography and PHPLC. Their structures were established on the basis of spectroscopic analysis and chemical evidence. The isolated compounds were tested using in vitro MTT assay for their cytotoxic activities against the K562, HL-60, CA46, HepG2, SW480 and SMMC-7221 cancer cell lines. Among them, compound 4 showed cytotoxicity against HL-60 and CA46 cancer cell lines with IC50 values of 25.98 and 20.42 µg mL−1, respectively.