Two new triterpenes mayteneri A ( 1 ), mayteneri B ( 2 ), and seven known compounds ( 3-9 ) were isolated from stems of Maytenus hookeri Loes. The chemical structures of compounds 1 and 2 were established by 1D, 2D NMR, HRESIMS analysis, and calculating electronic circular dichroism (ECD). The structures of known compounds 3 - 9 were determined by comparison of their spectral with those reported. Compounds 4 - 7 showed significant inhibitory activity for NLRP3 inflammasome, with the IC 50 values of 2.36-3.44 μ M.