RTV coatings are extensively utilized in high-temperature vulcanized (HTV) silicone rubber composite insulators for power transmission lines. However, prolonged exposure to intense UV radiation can lead to the aging of RTV materials, thereby compromising the operational reliability of power systems. In this study, TiO2/RTV nanocomposites with varying mass fractions were synthesized and subjected to UV aging tests. The effects of different TiO2 doping ratios on the surface micromorphology, mechanical properties, hydrophobicity, and electrical characteristics of TiO2/RTV before and after UV aging were systematically investigated using SEM, tensile strength measurements, hydrophobicity angle assessments, and flashover voltage tests. The results demonstrate that the incorporation of TiO2 nanoparticles significantly enhances the tensile strength and hydrophobicity of RTV, while also markedly improving its voltage resistance. After UV aging, the hydrophobic angle of pure RTV exhibited a more pronounced decline compared to that of TiO2/RTV nanocomposites, and the surface micromorphology indicated a more severe aging extent in pure RTV. Furthermore, the electrical properties of TiO2/RTV nanocomposites were substantially superior to those of pure RTV, underscoring their enhanced resistance to UV aging. This study provides a theoretical foundation for understanding the UV aging mechanisms of RTV materials. The selection of an optimal TiO2 doping ratio can effectively augment the anti-aging performance of RTV coatings, thereby extending their service life in harsh environmental conditions.