Non-metallic materials used for motor windings were prone to performance degradation with changes in temperature and time. The activation energy of non-metallic materials could be used to identify the thermal life of non-metallic materials by connecting the actual service conditions and accelerated aging conditions. Its value directly determined the temperature and aging time for the thermal life identification of materials. This article mainly introduced the current main methods of activation energy estimation, including thermogravimetric analysis, DSC analysis, combination of thermogravimetric analysis and thermal aging test, and thermal aging test evaluation methods. The specific implementation process of each method , the differences between the methods and the scope of application were given in detail, so as to facilitate the selection of determination methods for different evaluation materials.