Starting from the 3, 4-dimethoxybenzyl alcohol, 3, 3′, 4, 5′-tetrahydroxystilbene (piceatannol) was synthesized through bromation, Arbuzov Rearrangement followed by Wittig-Horner reaction and demethylation reaction. The effects of brominating agents, the temperature of Arbuzov Rearrangement, solvent in Wittig-Horner reaction, and demethylation agents were investigated .The optimal conditions were: phosphorus tribromide as the brominating agent, Arbuzov Rearrangement conditions of 100 ℃ for 1h and then 120 ~ 130 ℃for 3 ~ 4h, dimethylformamide as the solvent in Wittig-Horner reaction , dry aluminum chloride as the demethylation agent. The structure of the target molecules was confirmed by using IR、1H and 13C NMR spectra.