Surface discharge might make some difference on pollution layer of insulators, which probably affected the insulation performance of insulators. Based on surface discharging simulation experiment, artificially polluted silicone rubber specimens were taken advantages of to study the impact of surface discharge on pollution layer. Parameters such as microstructure and element were analyzed in this paper. Method was come up with to evaluate the fixation degree of pollution layer. Results indicated that: impact of surface discharge could make the pollution layer be more compact and firm. Fixation of kaolin was more serious than that of diatomite if other conditions were kept the same. Percentage of fixed pollution increased as surface discharge last for longer time. Generally fixation of pollution was more serious under DC voltage. However, difference brought by AC and DC voltage was unobvious if the period of surface discharging was too much shorter or longer. Intense degree of the discharge has significance on the fixation of pollution.