In this study, the nanocomposites were prepared by waterborne PU and nanomgrade SiO2, improved the end-ues Value. The effect of nanograde SiO2 additive on physical properties and vapor permeability and water resistance of nano-composite were researched. Although the thermal properties of the nonacomposites were tested by thermogravimetric analyzer (TGA) and Differential Scanning Calorimeter (DSC). Form results showed that the melt and degradation temperature of nanocomposites increased with increasing nanograde SiO2 Partides, and the Water resistance was the same results, but vapor permeability of nanocomposite film was decreased.