Abstract: Cables are of vital importance in power systems, and their aging problem has always been a research focus. This study focused on a mainstream cable in the market, conducting accelerated thermal aging experiments and acid and alkali resistance tests on the sheath. Through mechanical property experiments, it explored the performance changes of the cable at different thermal aging temperatures. The results show that the elongation at break of the cable varies regularly with the temperature of thermal aging. The parameter b of the Arrehenius equation and the actual value of activation energy were calculated by using the principle of time-temperature superposition, and the life model was established in combination with the retention rate of fracture elongation. The accuracy of the model was verified through the analysis of the elongation at break of the sheath after acid and alkali resistance, and the performance of the cable was comprehensively evaluated. The research finds that the mechanical properties of cables are significantly weakened after thermal aging, and the elongation at break decreases. From the perspective of thermal aging, the theoretical operating life of cable accessories is approximately 2.85 years.