Nanosized bismuth-doped tin dioxide/waterborne polyurethane nanocomposite materials were prepared by the blending method with self-made nanosized bismuth-doped tin dioxide slurry and waterborne polyurethane as raw materials.Experimental results indicated that the isoelectric point of nanosized bismuth-doped tin dioxide slurry was about pH 6 and the nanosized bismuth-doped tin dioxide was dispersed well with the composite dispersers of siloxane coupling agent of KH-550 and DP-518.The tensile strength and breaking extensibility of nanocomposite film containing 1.0% of the nanosized bismuth-doped tin dioxide were 9.23 MPa and 223%

respectively

and the transmittance of visible light was about 70%.The heat-insulation was over 8℃ in contrast to the pure waterborne polyurethane film.