Abstract: The traditional HTV silicone rubber composite insulator is widely used in transmission lines at home and abroad due to its excellent hydrophobicity and hydrophobicity mobility. However, with the development of UHV, more and more transmission lines need to pass through the areas with strong ultraviolet radiation, strong wind & sand and frequent bird pecking, where the harsh climate is prone to cause the decline of the external insulation performance of traditional HTV silicone rubber insulators and the damage of materials. In view of this situation, a comparison is made between the high polymer composite insulators, which has good UV-resistance performance and stable mechanical properties, and the traditional HTV silicone rubber insulators in terms of ultraviolet aging properties. The purpose of this study is to investigate the aging characteristics of polymer composite insulators in the northwest plateau area with strong ultraviolet radiation. The results of the study show that under continuous irradiation of short wave ultraviolet light, the epoxy material has a tensile strength and hardness much better than silicone rubber, and has good toughness that meets the purpose of bird pecking-resistance and treading-resistance; it is slightly inferior to silicone rubber in hydrophobicity, but still meets the requirements of outdoor operation.