The performance stability of silicone rubber for spacecraft in high and low temperature environment is very important to ensure the safe use of products. In this paper, the aging properties of silicone rubber materials for spacecraft at -40 ℃ , 100 ℃ and 200 ℃ were analyzed. The hardness, mass loss and tensile strength were used as the evaluation indicators of mechanical properties. The microstructure changes were reflected by infrared spectroscopy. The terahertz technology was used to study the optical properties and polar structure changes of the terahertz band refractive index spectrum analysis of silicone rubber after aging. The results show that the mass and tensile strength of silicone rubber decrease at low temperature of -40 ℃ , and the maximum change range is 2% . The hardness and refractive index are relatively stable. During the low temperature aging process, the chemical structure of silicone rubber is basically unchanged, and a slight oxidation reaction occurs. In the high temperature environment, the mechanical properties and optical properties of silicone rubber materials are greatly affected. With the extension of aging time, the quality and tensile strength generally show a downward trend, while the hardness and refractive index generally show an upward trend. When the temperature rises, the magnitude of these changes further increases. Terahertz refractive index spectroscopy analyzed the relationship between the polar structure of the material and the inter-molecular network structure and the oxidation and crosslinking of molecular chains during the aging process of silicone rubber. In the process of high temperature aging, the internal crosslinking by-products of silicone rubber volatilize, the organic content of side chains decreases, and the crosslinking between main chains occurs.