Abstract: In this paper, farnesyl bromide is successfully synthesized by using the highly efficient halide-replacement reagent Ph3PBr2 prepared in the lab, and the content of the bromide is analyzed with a chemical analytical method. Typical reaction conditions are: room temperature and 3 h in benzene as a solvent. Since Ph3PBr2 is easy to be decomposed in the presence of water, the solvent used in the reaction should be dried in advance. To get rid of HBr resulted during the bromo-substitution, pyridine was added to salt it out. The solution was distilled after the reaction was completed to remove the solvent, then hexane was added to resolve the bromide, and thus Ph3PO produced during the reaction could be removed. The reaction is easy to operate, with high yield, can be applied to other terpenols as well.