The hydrophobicity of polluted silicone rubber was improved rapidly under plasma jet treatment. It is an important phenomenon of the interaction between the plasma jet and the porous surface and shows a wide application prospect in the power system. In this process, the spatial characteristics and dose of plasma jet are very important. Therefore, the variation of hydrophobicity of polluted silicone rubber under plasma jet treatment was studied, and the spatial characteristics and dose of plasma jet on polluted silicone rubber were also investigated in the paper. The results show that the surface property (hydrophilic or hydrophobic) depended on the dose of plasma applied to the surface. The effective treated area was a circle, and the contact angles changed along the radial direction of the circle. This was attributable to the diffusion of plasma bullets on the surface and the distribution of plasma species. The plasma dose could be characterized by the energy density of the plasma applied on the surface. With the increase of plasma dose, the surface contact angles first increased rapidly and then decreased gradually.