To provide a new organic-inorganic composite film having excellent mechanical characteristics and gas barrier property, and to provide a method for preparing an organic-inorganic composite emulsion from which the above film can be manufactured.

The method for preparing an organic-inorganic composite emulsion comprises emulsion polymerization of hydrophobic polymerizable vinyl monomers in a water dispersion liquid of water-swellable clay mineral by using a surfactant, wherein the surfactant is an anionic surfactant, and the hydrophobic polymerizable vinyl monomer contains butadiene, isoprene or an acrylic acid ester.