This study was conducted to investigate the chemical constituents of Piper wallichii （Miq.） Hand.-Mazz. and evaluate their biological activity. Compounds were isolated by various column chromatographic methods, and their structures were elucidated on the basis of physical characteristics and spectral data. The 1, 1-diphenyl-2-picrylhydrazyl （DPPH）-scavenging activity and acetylcholinesterase （AChE）-inhibitory activity of the compounds were evaluated. Five compounds were obtained and identified as 8-C-β-D-glucopyranosylkaempferol-3-O-β-D-glucopyranoside （1）, 1, 2-dihydro-6,8-dimethoxy-7-hydroxy-l-（3, 5-dimethoxy-4-hydroxyphenyl）-N^1, N^2-bis-[2-（4-hydroxyphenyl）ethyl]-2, 3-naphthalene dicarboxamide （2）, goniothalactam （3）, aristololactam A IIla （4） and piperlonguminine （5）. Compound 1 was a new flavonol C-glycoside, 2 was a rare lignanamide, which was isolated from the family Piperaceae for the first time, and compound 3 was isolated from this plant for the first time. Among them, 2 showed potent DPPH-scavenging activity, with IC50 of 31.38 ± 0.97 μmol·L^-1; Compounds 2, 3, and 4 showed AChE inhibitory activity at 100 μmol·L^-1, with inhibition rates of 28.57% ± 1.47%, 18.48% ± 2.41% and 17.4% ±3.03%, respectively.
