Abstract: In order to study the surface discharge characteristics under the condition of insulation cleaning agent, three kinds of silicone rubber samples are completely soaked with water and cleaning agent, respectively, and the flashover voltage and leakage current of the samples are measured. Then, scanning electron microscopes and energy dispersive spectrometers are used to analyze the changes of structural components on the surface of the pollution layer. Finally, the arc emission spectrum of surface discharge is collected, and the effect of insulation cleaning agent on surface arc channel is analyzed by arc image extraction algorithm. The test results show that with the increase of pollution grade, the effect of insulation cleaning agent on surface discharge of wet pollution layer is more obvious. For the surface of the wet dirty layer, the insulating cleaning agent spreads and covers itself to form a dense protective film, and penetrates into it, preventing the soluble salt from dissolving, ionizing and exciting in the water, and volatilizing absorbs the heat of the surface dirty layer and prevents the electronic transition inside the dirty layer. For the arc channel, the insulation cleaning agent will further aggravate the distortion degree with the increase of pollution level, accelerate the energy dissipation of the arc channel, and strengthen the inhibition effect.