Mature seeds of Vernonia anthelmintica were separated and purified by using such methods as macroporous absorption resin, Sephadex LH-20 and HPLC preparative chromatography. Six compounds were obtained and their structures were identified by such spectrum techniques as 1H, 13C-NMR and MS. Compound 1-6 were identified as caffeic acid (1), 3-O-caffeoylquinic acid (2), 4-O-caffeoylquinic acid (3), 5-O-caffeoylquinic acid (4), 3, 4-di-O-caffeoylisoquinic acid (5), 3, 4-di-O-caffeoylquinic acid (6). Among them, compounds 1-6 were separated from this plant for the first time, while compounds 3-5 were separated from this genus firstly.