Much work over the last 10 years has focused on composites that exhibit a change in composition and structure over a nanometer length scale．Layered silicates like montmorillonite(MMT) dispersed as a reinforcing phase in a polymer matrix are one of the most important forms of such organic-inorganic nanocomposites to afford remarkable property enhancements relative to conventionally-scaled composites．This paper focused on preparation of PVAc／organic-MMT nanocomposite by γ-ray radiation polymerization．Being organized

affinity of montmorillonite (MMT) to organic substance is improved

and the molecular of VAc penetrate into layers of montmorillonite in this experiment．The intercalation polymerization was initiated by γ-ray radiation．In this process

the layers of montmorillonite were exfoliated and PVAc/organic-MMT nanocomposite was formed．XRD patterns shown after polymerization the d(001) basal spacing of MMT uptake from 2.44 to 3.68 or 4.41 nanometer．This indicated that the montmorillonite were exfoliated into layers of nanoparticles and dispersed in PVAc matrix．FT-IR spectrum shown the characteristic absorption of PVAc in the MMT particles separated from the nanocomposite and the position of peaks shift to high wavenumbers．This shown there is polymer phase in the MMT particles and there is an interaction between PVAc and MMT nanoparticles．SEM and TEM have also proved that the PVAc／organic-MMT is a kind of nanocomposite．We also have studied the tensile atrength and tensile elongation of PVAc／organic-MMT nanocomposites and the PVAc/organic-MMT blends．The results show that the nanocomposite have high tensile strength and tensile elongation than blends when the amount of MMT is same．