Bioactivity-guided fractionation of the MeOH extract from the roots of Sophora tonkinensis resulted in the isolation of a new pterocarpan glycoside (1) together with nine known compounds, maackiain (2), sophoranone (3), sophoranochromene (4), pinoresinol (5), syringaresinol (6), medioresinol (7), 4',7-dihydroxyflavone (8), calycosin (9), and genistein (10). The structure of the new compound was determined on the basis of spectroscopic analysis including NMR and CD data in combination with acid hydrolysis. Compounds 1-4 exhibited the inhibitory effects on LPS-induced nitric oxide production with IC50 values ranging from 13.6 to 33.0μM in RAW 264.7 macrophages.