Abstract: Perfluoroalkoxy (PFA), a melt-processable fluoropolymer, is widely used in high-end manufacturing fields where thermal reliability and cleanliness are required. In this work, the influence of fluorine gas treatment time on the end groups and thermal degradation kinetics of a TFE/PPVE copolymer was systematically investigated. FT-IR spectra show that the characteristic absorption bands of unstable groups, including R_fCOF, C—H and CONH₂, decrease markedly after fluorine gas treatment. TGA results indicate that fluorine gas treatment increases the 1% decomposition temperature and significantly suppresses mass loss at 380 ℃, while the overall degradation stage remains similar. Chang’s method was further used to analyze the kinetic parameters. All samples approximately follow first-order degradation in the 5%–90% conversion range, whereas the fluorine gas-treated PFAs exhibit much higher apparent activation energies than untreated PFA in the initial 0%–1% conversion range. These results demonstrate that fluorine gas treatment mainly improves the initial thermal stability of PFA and provides a kinetic explanation for its industrial application.