Abstract: To improve the electrical and hydrophobic properties of epoxy resins in switchgear equipment, the magnesium oxide nanoparticles (nMgO) are modified with silane coupling agent (KH560) and fluorinated silane coupling agent respectively, and characterized by FT-IR and XPS. And the epoxy composites of different concentrations (5%, 10%, 15% and 20%) are prepared with solution blending method, and characterized by testing dielectric constant, dielectric loss, conductivity and contact angle. The results show that the introduction of fluorine element can reduce the surface energy of the composites, and the hydrophobicity of the epoxy composites is significantly improved with the increase of the doping content, reaching 114° at 20 wt.%. The electrical properties of the epoxy composites all meet the requirements for the use of electrical equipment, with the dielectric loss being lower than the level of epoxy resin and the resistivity being higher than that of epoxy resin.