Abstract: To fill the gap in the synthesis of polychlorinated biphenyl isotope internal standard reagents in China, this study investigates the synthesis and characterization method of stable isotope-labeled 2,3,3’,4,4’,5-hexachlorobiphenyl-2’,6,6’-D₃. Using 1,2,3,4-tetrachlorobenzene-D₂ as the starting material, the intermediate 1,2,3,4-tetrachloroiodobenzene-D was obtained via iodination. Meanwhile, using 3,4-dichloroaniline as the material, 3,4-dichlorophenylboronic acid pinacol ester-2,6-D₂ was synthesized through three steps: hydrogen/deuterium exchange, diazotization iodination, and boration. The target product 2,3,3’,4,4’,5-hexachlorobiphenyl-2’,6,6’-D₃ was obtained via Suzuki coupling of the two intermediates. According to the amount of 1,2,3,4-tetrachlorobenzene-D₂, the overall yield of this synthetic route was 31.14%. The structure of the target product was characterized by ¹H NMR, gas chromatography and mass spectrometry. The chemical purity of the product was 99.04% and the abundance of deuterium isotope was 99.17 atom%D, and it can be used as a standard reference material for the detection of polychlorinated biphenyls.