A convenient method for the practical synthesis of piceatannol is described.Starting from the readily available 3,4-dimethoxybenzyl alcohol,through bromation、Arbuzov rearrangement、Wittig-Horner reaction and demethylation,we obtained the piceatannol.The product was confirmed by IR,1H NMR and 13C NMR.The antioxidant activity of piceatannol was evaluated with different antioxidant tests,including reducing power,free radical scavenging and hydroxyl radical scavenging respectively in vitro.The antioxidant activities were compared with resveratrol、TBHQ、BHT and catechin.The results showed that piceatannol had strong antioxidant activity.The reducing power and free radical scavenging ability were both higher than resveratrol、TBHQ、BHT and catechin.IC50 of piceatannol on scavenging free radical and hydroxyl radical were 16.57 μg/mL and 270.00 μg/mL.