Abstract: The antioxidant activities of three fractions partitioned by petroleum ether, ethyl acetate and water from ethanol extract of jackfruit peel were estimated using DPPH, ABTS and ferric reducing/antioxidant power (FRAP) methods. And the content of total polyphenols and flavonoids in each fraction were determined. The results showed that the content of flavoniods and polyphenols from ethyl acetate fraction were the highest and the value was 1.346mg/g and 1.102mg/g, respectively. However, the water fraction had the poor level of polyphenol and flavonoid content, which was 0.593mg/g and 0.029mg/g, respectively. The antioxidant activity of petroleum ether followed that of ethyl acetate part and the water fraction presented poor antioxidant activity. Furthermore, the ethyl acetate part showed an excellent antioxidant activity, inhibition ratio of which was 94% for DPPH radical and 99.1% for ABTS+radical. And its ferric reducing/antioxidant power reached 952.6μmol/L.