Prepared PVA/MMT nanocomposites with different PVA contents using polyvinyl alcohol and montmorillonite as raw materials,characterized the structure of composites by X-ray diffraction ( XRD) ,scanning electron microscopy ( SEM) . The results showed that the polyvinyl alcohol molecules come into the interlayer of montmorillonite achieved in nano-scale composite successfully,in the SEM picture we had observed the nano-composite microstructure.