Carbon nanotubes (CNTs)/natural rubber (NR) composites were prepared by the slurry blending method to get a better dispersion of CNTs in NR composites. The slurry blending method was a new method to improve and optimize the commonly used traditional method (the latex blending method). The treatment of slurry blending for CNTs/NR composites could reduce the agglomeration and settlement of CNTs than that of latex blending process. In order to show the superiority of this method, the morphology, mechanical properties, Payne effect, thermal conductivity, permittivity and dynamic mechanical properties of the composites prepared by the two methods were measured and compared.