Organo-hectorite were prepared by the intercalation of organic materials in interlayer of synthetic hectorite by the hydrothermal synthesis of hectorite. The hydrothermal synthesis of Li-hectorite or TEA-hectorite were carried out using silica and magnesium oxide with LiF or Tetraethylammonium salt. The basal spacing of organo-hectorite increases up to 39 Å by the intercalation of octadecylamine/HCl solution into synthetic Li-hectorite. The large expansion of interlayer distance well illustrates the application of organo-hectorite as inorganic filler of polymeric nanocomposite.