Abstract: The fluoropolymer insulated cable is the main system of aviation cable. Aviation cables with polytetrafluoroethylene (PTFE), fusible polytetrafluoroethylene (PFA) and perfluoroethylene propylene (FEP) as sheaths were selected for the study of their thermal decomposition characteristics with the thermogravimetric analyzer under different heating rates in nitrogen atmosphere. The results showed that the pyrolysis process of PTFE was only one stage, while that of PFA and FEP was differentiated into two stages respectively. At the same time, the initial decomposition temperature and 10% weight loss temperature of PTFE were both higher than those of PFA and FEP. Therefore, PTFE is less prone to thermal decomposition than PFA and FEP. The analysis of non-isothermal pyrolysis kinetics was carried out with the aid of four methods, including Ozawa, Kissinger-Akahira-Sunose (KAS), Starink and Friedman. The values of apparent activation energy calculated using the Ozawa, KAS and Starink methods were basically identical for the same material. However, the apparent activation energy values estimated with the Friedman method were slightly higher than those obtained with the other three methods. It was found that the initial apparent activation energy and average apparent activation energy of PTFE were both higher than the corresponding values of PFA and FEP, so the thermal stability of PTFE was the best in the whole pyrolysis process.