Abstract: In order to study the aging performance of composite insulators under the condition of significant temperature difference and intense ultraviolet radiation in the desert-gobi-wasteland area of Inner Mongolia power grid, thereby improving the operational maintenance standards of composite insulators, aging tests involving cold and hot aging, UV aging, and a combination of both are conducted on high-temperature vulcanized silicone rubber samples. It is revealed that UV aging test results in the greatest reduction of static contact angle of the samples, and the aging degree of ultraviolet aging on composite insulators is stronger than that of cold and hot aging, which can weaken or break some Si-C bonds and reduce the surface hydrophobicity, while the aging degree of first cold and hot aging and then ultraviolet aging on composite insulators is between the other two. There is an interaction between the two aging methods, leading to partial breakage of C-H bonds within the CH₃ groups of the material, thus affecting the overall performance. Relevant conclusions provide reference for the aging research of composite insulators and the application of such materials in transmission lines.