Siloxane-modified two-component waterborne polyurethane (Si-2KWPU) was synthesized by the reaction between siloxane-modified hydroxyl-functional polyurethane aqueous dispersion（Si-HPUA）,which were prepared by prepolymer process,with isophorone diisocyanate(IPDI), polypropylene glycol (PPG), dimethylol propionic acid (DMPA) and trimethylolpropane (TMP) as main raw materials, dihydroxybutyl terminated polydimethylsiloxane (DHPDMS) as modifier, and the hydrophilic-modified polyisocyanate. The polymer structure and properties was characterized respectively by FTIR、1HNMR and XRD、TGA,and studied the effect of silicone content on the performance of hydroxyl-functional polyurethane aqueous dispersion and the 2K-WPU film. The results showed that the particle size of the dispersion increased,the viscosity decreased,the water absorption rate and tensile strength of membrane decreased,the water contact angle and elongation at break increased,with the increase of conent of silicone.When the mass fraction of silicone was 5%,the membrane had the best comprehensive performance.Water absorption rate and the contact angle were respectively 6.2%, 94.96°;The decomposition temperature of 5% mass loss was 272℃.