In UHV transmission projects, with the continuous improvement of operating voltage level, the discharge caused by strong electric field intensifies the aging of composite insulator outer insulation material. The composite insulators will be subjected to higher field strength, and the resulting partial discharge may generate higher temperature. Therefore, the study of silicone rubber aging under the action of strong electric field and high temperature is more important, but it is difficult to accurately evaluate the aging characteristics only by relying on macroscopic characteristics. In this paper, a molecular model of polydimethylsiloxane was established based on molecular dynamics simulation to explore the structural evolution and microscopic characteristic variation of siloxane under the action of temperature and electric field, and to further study the change of mechanical properties of silicone rubber. It is found that temperature is negatively correlated with mechanical properties. There is a positive correlation between electric field strength and mechanical properties. This study provides an analytical method for predicting the macroscopic characteristics of silicone rubber material through the microscopic morphology, and then provides a reference for analyzing the microscopic mechanism of composite insulator aging and material optimization selection.

composite insulator; methyl siloxane; molecular dynamics; electric field strength; temperature