Abstract: Three pieces of XP-70 porcelain insulator string are taken as research objects, a numerical wind tunnel simulation model is established. Based on the Euler gas-solid two-phase flow analysis model, the pollution volume fraction is used to evaluate the pollution degree of the insulators, and the pollution characteristics of XP-70 insulators are analyzed by numerical simulation.The results show that the static pressure on the windward side of the insulator is the largest, and it collides with the pollution particles fiercely. At the same time, when the air fluid passes through the insulator, it is easy to form backflow on the leeward side and bottom of the insulator under the effect of turbulence. With the increase of pollution concentration, the pollution degree of the pollution monitoring points on the surface of insulator increases. The amount of pollution on the wind-ward side, leeward side and bottom area of the insulator increases with the increase of the wind speed and particle size, while the pollution amount of the pollution monitoring points on the cross wind area of the insulator decreases with the increase of the wind speed and particle size.