Lyoniside, β-sitosteryl β-D-glucoside, and monotropein and its methyl ester were isolated from the benzene-insoluble portion of the methanol extract of the wood of Tripetaleia paniculata SIEB. et ZUCC. The steric structure of lyoniresinol, the aglycone of lyoniside, was determined as formula (II) from the optical rotatory dispersion (ORD) and circular dichroism curves of its various derivatives (I, III to VI). The sugar moiety of lyoniside was determined as D(+)-xylose from the ORD curve of the sugar and from the gas-liquid chromatography of its trimethylsilyl ether, and the bonding was determined as β-linkage from the nuclear magnetic resonance spectrum of completely methylated compound. The position of sugar linkage was concluded as the methylol in 3-position from the hydrolysis of the completely methylated compound, followed by oxidation of the aglycone.