The chem. compositions in the seed of fried Vaccaria segetalis were analyzed. Compounds were isolated and purified by C18 reverse phase silica gel column chromatog., gel column chromatog., polyamide column chromatog. and preparative HPLC. Chem. structure was identified by determining physico-chem. constants and UV, IR, 1H-NMR, 1C-NMR, FAB-MS, et al. Four compounds were obtained and identified as (2S)-N,N,N-trimethyl tryptophane betabine, celereoin-6-C-arabinose-glucopyranoside, vaccaria flavonoid glycosides (apigenin-6-C-glucose-arabinose-4'-O-glucoside), celereoin-6-C-double-glucopyranoside. Among them, (2S)-N,N,N-trimethyl tryptophane betabine was first isolated from plants.