Poly (silicone-co-acrylate)/montmorillonite nanocomposite emulsion were prepared by in situ intercalative emulsion polymerization of acrylate and organosilicone, in the presence of organic modified montmorillonite (OMMT) with different OMMT contents (0, 0.5, 1, 1.5, and 2 wt %). The nanocomposite emulsions were characterized with X-ray diffraction (XRD), laser light scattering, fourier transform infrared (FTIR), rheological measurements, surface tension, drying speed, and water absorption property. Results showed that OMMT could improve the properties of emulsion, in other words, the properties of nanocomposite emulsion were better when compared with those of the silicone-acrylate emulsion. The properties of nanocomposite emulsion containing 1 wt % OMMT was the best one, and obtained the following advantages: smaller particle size, faster drying speed, shorter curing time, smaller surface tension, bigger apparent viscosity, and improved resistant water by the incorporation of OMMT. (c) 2006 Wiley Periodicals, Inc.