Abstract: Referring to ISO 11358-2:2021 and GB/T 11026.1—2016, Arrhenius curve equation and activation energy of eight nuclear cable crosslinking materials were obtained by thermogravimetric analysis (TG) and conventional analysis(CA), respectively. By comparing the results, characteristics and differences of activation energies obtained between TG method with weight loss of 5% and 10% (mass percentage) and CA method were analyzed. Results indicated that, activation energy obtained from TG method with weight loss of 5% was lower than that with weight loss of 10%, and there was no clear pattern compared to the results obtained from CA method. For nuclear-grade crosslinked polyolefin materials, activation energy obtained from TG method with weight loss of 5% was close to the result obtained from CA method. While, for ethylene propylene rubber(EPR)materials, a smaller weight loss should be selected.