Due to the increasing depletion of natural resources,the development of new energy was particularly important.Owing to the large reserves and renewable,the biomass resources had called many scholars attention.And pyrolysis was an effective way to use biomass resources.But at this stage there were no good explanations of biomass pyrolysis mechanism,especially lignin.So the synthesis of lignin model compounds with characteristics linkages and the study of their pyrolysis mechanisms were meaningful.One biphenyl lignin dimer,dehydrovanillin,was synthesized.The chemical structure was characterized by Fourier transform infrared spectroscopy(FT-IR),as well as 1H-and 13C-NMR.The prolysis behaviors were analyzed by thermal gravimetric analysis(TG),and pyrolysis-gas chromatography combined with mass spectrometry(Py-GC/MS).And the prolysis mechanism was explained by density functional theory(DFT).The FT-IR and 1H-,13C-NMR showed that the structure of the dimer was clearly identified and the purity was high.The TGA showed that the maximum weight loss peak of the dimmer occurred in 325 ℃.And the prolysis products from dehydrovanillin were quiet different in different temperatures,concluding carbon dioxide,2-methoxy-4-methylphenol,vanillin,3-hydroxy-4-methoxybenzoic acid and other biphenyl structures.