Abstract: The in suit intercalated polymerization of vinyl acetate (VAc) and organophilic montmorillonite (OMMT) was initiated via emulsion polymerization and obtained polyvinylacetate (PVAc)-nano-OMMT hybrid. Twofold blend composed of PVAc-nano-OMMT/PP-EVA was prepared by twin-screw extruder way, and X-ray diffraction (XRD) result shows that the structure of PVAc-nano-OMMT/PP-EVA is be treated as exfoliated nanocomposite structure during application of higher shear stress to system, and transmission electron microscopy (TEM) observation gives the same result directly. Thermo gravimetric analysis (TGA) results show that the initial decomposition temperature of PVAc-nano-OMMT/PP-EVA is greater than that of PP-EVA and nano-OMMT/PP-EVA , the existence of PVAc-nano-OMMT makes composite better thermal stability. In the PVAc-nano-OMMT/PP-EVA composite, PVAc-nano-OMMT has better toughness. Limiting oxygen index (LOI) and cone calorimeter test indicate that LOI of PVAc-nano-OMMT/PP-EVA is 24.1%, and has lower heat release rate, effective heat of combustion, smoke release course, and better flame retardancy.