Organoclay has a low electrical conductivity and a proper dielectric constant which makes it to be used as a gate insulator. In a dry form, the organoclay exists in aggregates of montmorillonite platelets and very little surface area of the montmorillonite is exposed. For uniform dispersion of the clay aggregated, PA-66 and organically modified Na-montmorillonite (OMMT) were melting blended by using an internal mixer. The crystalline change and effects of intercalation were investigated with X-ray diffraction. Results of thermal properties, micro-structure, surface resistance and crystallization behavior indicated that OMMT had obviously effects on PA-66. DSC results showed that the existent of OMMT had effect on PA-66/OMMT nanocomposites and OMMT content had important effects on the scatter of OMMT in PA-66 matrix.