A method for making a thermal interface material includes following steps. A substrate having a plurality of CNT arrays arranged thereon and a number of first interspaces defined between the CNT arrays is provided. A container is provided and the substrate with the CNT arrays is disposed into the container. A number of low melting point metallic nanoparticles is provided and filled in the first interspaces. The low melting point metallic nanoparticles in the container is heated into a liquid state, and the low melting point metal nanoparticles in liquid state is combined with the CNT arrays to form a composite material on the substrate. The composite material is peeled off from the substrate, and a thermal interface material is obtained.