We have studied tho oligomerization of tetrafluoroethylone and its application, Oligomerization of tetrafluoroethylene catalyzed by fluoride ion produced an easily separable mixture of oligomers in 78% yield.The structures of the tetramers and pentamer were confirmed as Ⅰ and Ⅱ respectively.The sulphonate derivative of the pentamer (Ⅵ) has been used satisfactorily as a degreasing agent for non-cyanide electroplating on copper.