Nine compounds were isolated from 95% ethanol extract of the roots of Tagates erecta by silica gel column chromatography and Sephadex LH-20 chromatography. Their structures were identified by spectroscopic data as 5-hydroxymethylfurfuryl methyl succinate (1), 5,7,3'-trihydroxyl-3,6,4'-trimethoxylflavone (2), syringic acid (3), 5,7,4'-trihydroxyl-3,6-trimethoxylflavone (4), patuletin-4'-methoxyl-7-O-β-D-glucopyranoside (5), patulitrin (6), 5,3'-dihydroxyl-3,6,4'-trimethoxylflavone-7-O-β-D-glucopyranoside (7), (2,2'-biththiophen)-5-ol (8), and 3-hydroxyl-4-methoxyl benzoic acid (9). Among them, compound 1 is a new disubstituted succinate and compound 8 was isolated from a natural resource for the first time. Compounds 2, 4, 5 and 9 were isolated from this genus for the first time. By measuring the biological activity and virulence of different compounds against soybean cyst nematode, it has found that compounds 1-8 exhibited a toxic effect on soybean cyst nematode, and ED₅₀ values indicate that compounds 3 and 7 are the most potent, with ED₅₀ values of 0.008 μg·mL^-1.