In order to further investigate the principle of contamination deposition on electrical insulator surface,the settlement process of polluted particles on the electric insulator surface is analyzed,and a simplified model todescribe the polluted particles and the air flow field is established.Then,by adopting the hydromechanical method,the force and the motion processes of polluted particles in the air and the boundary layer are analyzed,and a motionmodel of polluted particles before their adsorption on the insulator surface is established,with the correspondingcalculation results being also discussed.It is demonstrated that the contamination deposition rate on the upper surfaceof electric insulator is greatly higher in the area with larger polluted particles,while in the area with smallerpolluted particles and stronger wind,the rate on the lower surface is greatly higher.Moreover,it is found that thepollution level of electrical insulator surface can be reduced by controlling the consistency of polluted particles witha diameter of less than 20 μm.