The booster sheds were installed at the electric field turning point of the clean composite insulator to improve the anti-contamination ability of insulator and increase the creeping distance, thereby improving the external insulation property from the source. The purpose was to improve the anti-contamination effect of cantilever composite insulator for overhead contact system in the heavy contaminated area of the salt-lake, and further reduce pollution flashover accidents. A multi-field and single-phase coupling finite element model of contamination insulator in wind tunnel was established by using COMSOL Multiphysics electric field, flow field and particle tracking field, based on the theories of power frequency electromagnetic field and gas-particle two-phase flow. The effects of suspension mode and environmental factors on the contamination characteristics were analyzed numerically, taking the collision coefficient and the distribution coefficient as the characterization parameters of insulator contamination. Results showed that the collision coefficient increased with the increase of wind speed and increased first and then decreased with the increase of particle size, when the insulator was installed horizontally or obliquely. The collision coefficient reached minimum when the wind direction was 0°. The effect of suspension mode on the collision coefficient was greater when the wind speed or particle size was larger or the change range of wind direction was between negative thirty degree and thirty degree. The relationship between the distribution coefficient of the sheds and the wind direction was in line with the " γ” type when the wind speed was 30 m/s and the particle size was 15 μm. The collision coefficient between the two booster sheds and the collision quality of the single shed adjacent to the booster sheds greatly reduced with the installation of the booster sheds.