To study the chemical constituents of the whole plant of Fallopia cynanchoides (Hemsl.) Harald. var. cynanchoides,seventeen compounds were isolated and purified by various modern chromatographic techniques,including normal phase and reverse phase silica gel column chromatography,Sephadex LH-20 column chromatography,semi-preparative HPLC.NMR,MS and other related spectroscopic analyses were used to identify their structures.The isolated compounds were identified as lyoniresinol (1),β-D-(1-O-acetyl-3,6-O-trans-diferuloyl)-fructofuranosyl-α-D-2′,4′,6′-O-triacetylglucopyranoside (2),p-hydroxyphenethyl trans-ferulate (3),(3S,5R,6S,7E)-3,5,6-trihydroxy-7-megastigmen-9-one (4),2,3-dihydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone (5),2-methyl-5-(2′-oxo-4′-hydroxypentyl)-7-hydroxychromone (6),2-(2′-hydroxypropyl)-5-methyl-7-hydroxychromone (7),2,5-dimethyl-7-hydroxychromone (8),2-methyl-5-acetonyl-7-hydroxychromone (9),emodin (10),quercetin (11),(+)-taxifolin (12),3,7-dimethoxy-5,3′,4′-trihydroxy-flavone (13),caffeic acid methyl ester (14),protocatechuic acid ethyl ester (15),(2aS,3aS)-lyciumamide D (16),and 3-acetyl-4,5-dimethoxy-benzoic acid (17).This was the first report of the presernce of compounds 1-7,9,13,14,16,and 17 in the genus Fallopia. Compounds 1-9 and 11-17 were first identified from F.  cynanchoides var. cynanchoides.The 70% ethanol extract showed obvious ABTS⁺ radicals scavenging effect with IC₅₀ value of 14.21 μg/mL;further in vitro bioassay indicated that compounds 1-3，11，13-17 showed moderate ABTS⁺ radicals scavenging activities. Among them,compounds 1,13,14 demonstrated significant antioxidant effects with IC₅₀ values of 15.30,16.97 and 17.53 μmol/L,which were better than that of positive medicine trolox (IC₅₀ 23.55 μmol/L).These findings provided an important foundation for the development and utilization of plant resource of F.  cynanchoides var. cynanchoides.