The invention discloses a synthesis method of a polysubstituted biphenyl halide liquid crystal intermediate, and belongs to the technical field of polysubstituted biphenyl halides. The method comprises the following steps: A, taking polysubstituted phenylboronic acid or polysubstituted boric acid ester as raw materials, performing Suzuki coupling reaction with substituted-4-halogenated aniline to obtain polysubstituted benzidine, wherein the reaction temperature is controlled to be 50 to 150 DEG C, and the reaction time is controlled to be 3 to 10h; B, the polysubstituted benzidine is reacted with a diazotized reagent in a solvent under an acid environment, the reaction temperature is controlled to be 20 to 10 DEG C, so that a diazonium salt is obtained, then halogen exchange is performed to obtain polysubstituted biphenyl halide, the exchange temperature is controlled to be 0 to 60 DEG C and the time is controlled to be 3 to 24h. According to the invention, iodo-derivatives, which cannot be prepared in the prior art, are obtained, and an effect better than that of the prior art can be realized by applying the iodo-derivatives to the synthesis of single crystal.