Along with our country " west-east electricity transmission " project and UHV projects,HTV-silicon rubber has been more and more widely used in the western regions of China,such as xining, Lhasa, hami and other regions, has strong solar radiation, long sunshine time, but the region environment humidity conditions are different. Therefore, it is necessary to study the Effect of UV Radiation on HTV-Silicon Rubber under different humidity. In this paper, the extraction of relative humidity variable, under different humidity conditions,HTV silicone rubber material taken for artificial ultraviolet aging experiment, to explore under different humidity conditions,HTV silicone rubber material’s ultraviolet aging properties. Experimental samples of artificial ultraviolet aging experiment taken in static contact angle test, hardness test, fourier transform infrared spectroscopy (FTIR) analysis, then integrate the test data and make theoretical analysis.The experimental results show that both samples hardness are larger, the flexibility are reduced; their both surface static contact angle are decreased, the hydrophobic are part of the loss; their both surface roughness are bigger,and a part of filler is leaked; FTIR of peak area of Si-CH3 and Si-O-Si keys absorption peak are reduced, shows a portion of the Si-CH3 and Si-O-Si keys is interrupted into free radicals; UV radiation has a certain influnce on HTV silicone rubber.Humidity variable has two contray sides influence on ultraviolet aging characteristics of HTV silicone rubber material,its process is complicated.