This paper reports on the characterization of the nano-wool fibrous materials that were obtained by using a patent pending technology to pulverise natural wool fibers into nano-scale particles in terms of morphology. After three steps pulverization, the nano-wool particles are in fibrous shape with length of around 80–300 nm, diameter of 10–80 nm and the mode particle size was around 100 nm. The surfaces of cotton fiber in a fabric treated with the nano-wool fibrous materials were covered a film of nano-wool fibrous materials, which change the water absorbency, thermal conductivity and Q_max values of the fabric significantly. These results indicate that the nano-wool fibrous materials can be used as a functional material for cotton fabrics treatment.