A determination method of ultra performance liquid chromatography-triple quadrupole mass spectrometry( UPLC MS /MS) was developed for qualitative analyzing of anthocyanins. After black soybean was extracted through petroleum ether,the reflux was extracted by 6% formic acid,the supernatant was then ultrafiltrated. The analysis was carried out by ACQUITY UPLC BEH C18column( 2. 1 mm × 50 mm,1. 7 μm) as the chromatographic column,6% formic acid and acetonitrile as the mobile phase gradient elution. In electrospray ionization( ESI) positive ion mode,electrospray positive ion multiple reaction monitoring( MRM) was used for monitoring. Six kinds anthocyanins including cyanidins,peonidins,petunidins,delphinidins,pelargonidins and malvidins,totally 15 anthocyanins were detected. Among these 15 anthocyanins,8 compounds,cyanidin-3,5-diglucoside,cyanidin-3- rutinose,peonidin-3,5-diglucoside,peonidin-3-galactoside,malvidin-3-galactoside,malvidin-3-glucoside,petunidin-3-galactoside and petunidin have not been reported in any studies of anthocyanins in black soybean. UPLC MS /MS was a successful method because it is simple,accurate,rapid and highly selective.