Abstract: Silicone rubber insulators are widely used in distribution lines and equipment, while composite insulators may threaten their operation safety under the condition of serious fouling. In order to analyze the influence of insulating cleaning agent on composite insulator material, the swelling characteristics of silicone rubber material in different cleaning agents and the influence of silicone rubber material on electrical properties were studied. The results showed that the swelling of silicone rubber in the first four hours of cleaning agent was very obvious, the change rates of mass and diameter were 31% and 15%, respectively. When the soaking time was 24 hours, the change rate of mass and diameter were 47% and 20%, respectively. The electrical properties of silicone rubber have not changed before and after swelling, and the dielectric loss of silicone rubber before and after swelling has no change. The dielectric loss tan of 1000Hz is stable at 0.42 μ m 0.48. The interpole capacitance decreased from 6.54pF to 4.80pF with the swelling time. The tensile strength of silicone rubber decreased slightly by 22.7% after swelling.