The invention relates to a synthetic method of a boceprevir intermediate, namely (1R, 2S, 5S)-6, 6-dimethyl-3-aza-bicyclo-[3. 1. 0] hexane-2-carboxylic acid methyl ester hydrochloride, belonging to the technical field of drug synthesis. The synthetic method solves the problems of high cost, complex reaction, low yield, and the like of the synthesis of the boceprevir intermediate in the prior art. The synthetic method comprises the following steps of carrying out amino protection on 6, 6-dimethyl-3-aza-bicyclo-[3. 1. 0] hexane hydrochloride which is taken as an original raw material; then reacting 6, 6-dimethyl-3-aza-bicyclo-[3. 1. 0] hexane hydrochloride with 1, 2, 3, 4-tetralin-1-naphthylamine for 3-4 hours at 30-35 DEG C under the action of a hydrogen drawing reagent by taking 4, 4'-difluoro benzophenone as a chiral inductive agent; finally removing an amino protecting group, and adding acid to form salt to directly obtain a final product. The synthetic method disclosed by the invention has the advantages of low cost, simple reaction condition, few reaction steps, short time and high purity and yield of the final product, namely the boceprevir intermediate.