A mycochemical investigation on the medicinal mushroom Amauroderma rugosum led to the isolation of 30 compounds, including 14 sterols, 6 phenolic constituents, 5 unsaturated fatty acids, and 5 other compounds. The structures of these compounds were elucidated by comparison of their nuclear magnetic resonance spectroscopic and mass spectrometry data with literature data. Among them, compound 27 was obtained as a new natural compound, and compounds 2-4, 7-13, and 15-30 were isolated from the genus Amauroderma for the first time. Sterols and unsaturated fatty acids showed anti-inflammatory and antiproliferative activities in vitro. Compounds 5 and 6 showed the highest inhibitory effect on nitric oxide production in lipopolysaccharide-induced murine macrophage RAW264.7 cells, with half maximal inhibitory concentration (IC50) values of 27.6 ± 2.1 μM and 15.3 ± 2.0 μM respectively. Compound 17 exhibited the strongest inhibition against HepG2 and MDA-MB-231 cell lines, with IC50 values < 25 μM. This study not only enriches the understanding of the diversity of chemical constituents in A. rugosum, but it also provides a basis for further development and utilization of A. rugosum as a source of new potential antitumor or anti-inflammatory chemotherapy agents.