This research is to investigate study the flavonoids from stems of Nelumbo nucifera and the cytotoxic activities of iso- lated compounds. The constituents were separated by column chromatography,and their structures were elucidated by spectroscopic data analyses. The isolated compounds were evaluated for cytoxic activities by MTT method. Twelve compounds were isolated and identified as rhamnazin-3-O-beta-D-glucopyranoside (1), luteolin-3', 4'-dimethylether-7-O-beta-D-glucoside (2), kaempferol-3-O-beta-D-xylopyranosyl-(1-->2)-O-beta-D-glucopyranoside (3), quercetin-3,3'-di-O-beta-D-glucopyranoside (4), 1, 8-dihydroxy-3,7-dimethoxyxanthone (5), isorhamnetin-3-O-beta-D-glucopyranoside(6) , kaempferol(7), isorhamnetin (8), quercetin(9), astragalin(10), hyperoside (11) and 1-hy- droxy-3,7,8-trimethoxyxanthone(12). All compounds were isolated from stems of this plant for the first time, and compounds 1-5 were firstly isolated from the family nelumbonaceae. Compounds 24 and 6 showed significant cytotoxic activities against BEL-7402 carcinoma cell lines at a concentration of 1 x 10(-5) mol x L(-1) with the inhibitory rate of 67.36%, 53.25%, 57.78%, 60.13% and 52.11%, respectively.