Abstract: The components of surface contamination of insulators outdoors are very complicated, and the surface conductivity characteristics and contamination flashover voltage of insulators are significantly different under the influence of different pollution components. Four typical pollution components were selected for experimental research, and the surface leakage current and flashover voltage of insulators painted with different pollution components were compared and measured to obtain the influence characteristics of the pollution components on leakage current and flashover voltage of the insulators. The test results show that the maximum leakage current of insulators increases with the increase of humidity and soluble matter adhesion density（SCD）. When the SCD of different contaminants is small, the discriminability of insulators is not very high. The flashover voltage of insulators is mainly related to the conductivity, solubility, ionization characteristics and composition of insoluble contaminants as well as their interaction. The insulator flashover voltage of different single inorganic salt contamination components from low to high is as follows: NaCl, NaNO₃, MgSO₄, CaSO₄. The flashover voltage of insulators polluted by different mixed inorganic salts shows an upward trend with the increase of the content of CaSO₄ in the mixed contamination.