Abstract: Anthocyanidins in Euphorbia pulcherrima were extracted and identified by use of UV-vis spectrophotometry, high performance liquid chromatography (HPLC) and mass spectrometry (MS). Anthocyanidin extract in methanol showed 3 absorption peaks, at 270, 340 and 520 nm, in the UV-vis spectrum, with bathochromic and hypsochromic shift with methanol+AlCl3 and methanol+AlCl3+HCl, respectively; the ratio of the absorbance at 440 nm to that at 520 nm was 0.29. No fluorescence occurred under UV irradiance, and 5 absorption peaks occurred at 270 nm after HPLC. Five molecular ion peaks (m/z) occurred on MS: 595, 381, 611, 587 and 571, respectively, and monosaccharides in the extract were identified as rhamuose and glucose on HPLC. These results suggest that anthocyanidin in E. pulcherrima mainly include cyanidin 3-rutinoside, delphinidin 3-rutinoside, cyanidin 3- benzoylglucoside, delphinidin 3-benzoylglucoside and an unknown component.