A method for transferring TCPX (.alpha., .alpha., .alpha.', .alpha.'-tetrachloro-p-xylene) into TFPX (.alpha., .alpha., .alpha.', .alpha.'-tetrafluoro-p-xylene) is disclosed, which comprises the following steps: (a) providing a first reactant comprising TFPX; (b) mixing the first reactant with alkali metal fluorides, TCPX and phase transfer catalyst(s) to form a mixture, wherein the alkali metal fluorides is KF, CsF, NaF, LiF or the combination thereof, the phase transfer catalyst(s) is quaternary ammonium salt, quaternary phosphonium salt or the combination thereof; and (c) heating the mixture.