Abstract: The new progress in polyolefine/ montmorillonite,polystyrene/montmorillonite,rubber/montmorillonite nanocomposites was summarized.The structure and properties of polymer/montmorillonite nanocomposites,and the principles of organic modification of montmorillonite were described,the mechanisms of three preparation methods of polymer/ montmorillonite nanocomposites were also introduced.It was pointed out that modification of polymer by grafting,to raise the compatibility with organic-montmorillonite,was the ke...