<p>Changes in the mechanical properties of silicone rubber (SR) during long-term use can affect its comprehensive electrical–thermal properties and make it prone to failure. This paper adopts a combination of experimental and simulation methods to study the electrical–thermal–mechanical comprehensive performance change law of SR materials. Firstly, the ZnO/OMMT/SR model was constructed based on molecular dynamics software to analyze the network structure of internal intercalated bridges, and the effects of ZnO content on the electrical, thermal, and mechanical properties of SR were further investigated experimentally; finally, the electric field distribution of SR was investigated using Comsol simulation software. The experimental results show that when the doped 20% ZnO, the elastic modulus, and Payne effect of SR are optimal, the thermal conductivity of SR is also increased and the glass transition temperature is lowered; the three-dimensional lattice structure of intercalated bridges restricts the dipole motion and carrier migration, and the electrical performance shows the increase in resistivity, the increase in dielectric constant, and the decrease in dielectric loss. It was demonstrated that SR doped with 20% ZnO improves the boundary electric field distribution. This work is of great significance for coordinating the improvement of the electrical–thermal–mechanical performance of cable accessories.</p> Graphical abstract <p>Thermal conduction pathways within microstructures and simulation models</p>