Organo-magadiite was prepared by sililation of γ-aminopropyltriethoxysilane (APS) with interlayer Si-OH groups in the presence of gallery expander dodecylamine (DDA) in ethanol. The interlayer surface sililation were performed by the vaporization of ethanol from the slurry composed of APS, DDA, H-magadiite and ethanol. XRD analysis of dried-powder resulted in well-ordered large d-spacing of 38.5-52.1 Å, promising new application fields. This result should offer a promising route leading to the preparation of organo-layered materials that a various functional group are bonded chemically in interlayer surface.