In order to explore the composition of bioactive constituents in Kummerowia striata(Thunb) Schindl, its crude extract was isolated and purified by silica column chromatography, sephadex chromatography and recrystaltization. The chemical structures were determined by related physical properties, spectroscopic data or standard compounds. As a result, eight flavonoids were obtained from Kummerowia striata (Thunb) Schindl and identified as apigenin (1), kaempferol (2), quercetin (3), isoquercitrin (4), rutin (5), luteoloside (6), isovitexin (7) and isoorientin (8), together with β-sitosterol (9). Except apigenin and quercetin, the other seven kinds of compounds were isolated from this plant for the first time.