A composition for a thermal interface material is provided. The deficiencies of low thermal conductivity and high thermal resistance in the conventional thermal interface materials are resolved. The CNT-LC thermal composite structure is formed by using carbon nanotube with high thermal conductivity and liquid crystal polymer with the well-ordered structure. The thermal interface material thereby has a high thermal conductivity. The added amount of carbon nanotube is less than the added amount of metal or ceramic powders in the prior art for improving the dispersion process. The CNT-LC thermal composite structure and the phase change resin are compatible without phase separation. The thermal interface material has a phase change temperature about 45˜75° C. Any holes, gaps and dents on the surface of device are filled at the normal operating temperature of device to reduce the thermal resistance of the entire device.