The invention discloses a perfluorination method for end group of fluorine-containing polymer. The method comprises the following steps of: mixing the fluorine polymer with an end group stabilizing reagent, standing or stirring to convert a -COF group and a -COOH group in the polymer into a -CF3 group, wherein the end group stabilizing reagent comprises the following three components: (1) SF3Ra; (2) anhydrous hydrofluoric acid AHF; and (3) one or mixture of more than any two of diethylene glycol dimethyl ether, pyridine, methylene dichloride and trichlorofluoromethane, and the reaction temperature of the perfluorination method for the end group ranges from 0 DEG C TO 100 DEG C. In the method, only specific group in the fluorine polymer is selected to be converted into -CF3, rather than that -CH2- in a polymer molecule chain with the fluoride gas fluorination process is fluorinated into -CF2-.