In this study, it was found that the ethyl acetate soluble fraction of Musa basjoo flowers was a rich source of antioxidant, due to its high total phenolic contents and significant antioxidant activity. Ten phenolic compounds were isolated from this plant. They are gallic acid (1), caffeic acid methyl ester (2), guaiacylglycerol (3), 3-(3,4-dihydroxyphenyl)-acrylic acid 1-(3,4-dihydroxyphenyl)-2-methoxy carbonyl ethyl ester (4), thero-guaiacylglycerol 8-O-beta-d-glycopyranoside (5), quercitrin (6), buein (7), (2R, 3S)-5,7,3',4',5'-pentahydroxyflavanonol (8), isoquercitrin (9) and 1,7-bis(3,4-dihydroxyphenyl)-hepta-4E, 6E-dien-3-one (10). In addition, compounds 1, 2, 4, 6, 7, 8, 9 and 10 possessed potent strong free radical scavenging activity. Compounds 1 and 10 with powerful activity showed the higher content, implying important roles of 1 and 10 for the antioxidant activity of Musa basjoo flower. The study suggested that components of Musa basjoo flower possessed good antioxidant capacities and the species could be used in the prevention of diseases related to oxidant by-products of human metabolism.