A method for preparing an organic-inorganic hybrid porous insulation coating composition includes steps of: adding sepiolite nanoparticles that have been surface-treated with silane or dimethyl ammonium chloride to a thermal-resistant resin solution; and stirring the thermal-resistant resolution solution containing the sepiolite nanoparticles at 3600 rpm or more for 30 minutes or more. The thermal-resistant resin solution includes at least one thermal-resistant resin selected from the group consisting of polyamide-imide, polyester, polyester-imide and polyamic acid.