Waterborne epoxy resin／silica sol hybrid dispersions were prepared by in-situ dispersion of graft epoxy resin with both the silica sol and water simultaneously. The hybrid interaction between the graft epoxy resin and the silica sol with different particle sizes was observed through the measurements of FT-IR spectra and ζ potential．Compared with the graft epoxy resin water dispersion

the hybrid dispersions exhibited lower viscosity and smaller particle size. In this case

a mechanism of forming the hybrid water dispersion was proposed and discussed．Some surface properties of films prepared from these hybrid water dispersions were measured．The higher hardness and better water resistance for such surfaces of films were observed

resulting from the enrichment of silica sols on the surfaces of the hybrid films．