The invention discloses a preparation method of an aligned carbon nanotube/natural rubber composite material. Firstly by a solution blending method, carbon nanotube is added into a toluene solution ofnatural rubber to prepare mixed latex; then under the action of shear force of a flow field, orientation of carbon nanotube is induced. Nano-scale aluminum nitride is used together with the carbon nanotubes, and the volume ratio of the nano-aluminum nitride to the carbon nanotubes is 3:2. After orientation of the carbon nanotubes through mechanical shearing, the composite material shows obvious anisotropy. By using two thermal conductive fillers (aluminum nitride and carbon nanotubes) with different shapes, filling modification of natural rubber is carried out. With the cooperative use of aluminum nitride and carbon nanotubes, the thermal conductivity of the composite material is improved obviously in comparison with the application of micron-sized aluminum nitride. When the volume ratioof nano-aluminum nitride to carbon nanotubes is 3:2, the thermal conductivity of the composite material is the best, and the mechanical properties is gradually improved with the increasing of the carbon nanotube content.