In the research work, "click" chemistry was used to modify waterborne polyurethane (WPU) with silane coupling agent (SiCA) functionalized nano-silica. The modified WPU (CWPU) was characterized by FTIR, scanning electron microscope (SEM), thermogravimetric analysis (TGA) and contact angle measurement. The experiment results show that the modification can improve the thermal stability, hardness, and water or weather resistance of CWPU. (C) 2011 Elsevier Inc. All rights reserved.