Using p-xylene as starting material, anhydrous hydrogen fluoride as solvent and catalyst, under 4.0-5.0 MPa condition, 1,4-dimethyl-2-(trifluoromethyl) benzene and byproduct 1,5-dimethyl-2-(trifluoromethyl)benzene had been synthesized through Friedel-Crafts reaction and fluoridation.The structure of product was confirmed by NMR and IR, and nucleophilic rearrangement had been considered in this process theor.