In order to search a novel PTP1B inhibitor, [2´-bromo-6´-(ethoxymethyl)-3´,4´-dimethoxy-phenyl]-(2,3-dibromo-4,5-dimethoxy-phenyl)-methanone 8 was synthesized in 7 steps with an overall yield of 21.9%, employing bromination, Friedel-Crafts reaction and nucleophilic substitution reaction as key steps. The structure of compound 8 was determined by 1H-NMR, 13C-NMR and infrared absorption spectra. Compound 8 was screened against protein tyrosine phosphatase 1B (PTP1B) with the colorimetric assay. The result indicated that compound 8 displayed good inhibitory activity against PTP1B (Inhibition 73.83% at 20 mg •L-1).