Waterborne polyurethane/halloysite nanotubes nanocomposites were prepared by modified halloysite nanotubes (HTs) with chitosan (CS). Modified HTs were characterized by Fourier transform infrared spectroscopy, elemental analysis, and thermogravimetry, which verified that CS was successfully assembled onto the HTs surface. The chitosan-modified halloysite nanotubes (CHTs) were uniformly dispersed in WPU matrix through the reaction with polyurethane prepolymer, and acted as chain cross-linker as well as reinforcing filler, which increased the cross-linking density of nanocomposites. The experimental results showed that the strong interfacial interaction and hydrogen bonding interaction between CHTs and WPU improved the degree of micro-phase separation, thermal properties, mechanical properties and surface properties of nanocomposites. The tensile strength and elongation at break were simultaneously enhanced when the CHTs loading was below 2 wt%. (C) 2015 Elsevier B.V. All rights reserved.