Objective To synthesis the high antioxidant activity trans-3,4,5,4'-tetramethoxystilbene. Methods Tetrahydro- furan was used as solvent, 3,4,5-trimethoxybenzoic acid aminobenzoic was used as the starting material, after reduction re- action and halogen, Grignard reagent was preparated, with condensation of the star anise aldehyde to preparate target com- pounds. Results The target compound was determined by MS and 'H-NMR. Conclusion The trans-3,4,5,4'-tetrameth...