CNT (carbon nanotube) was purified by acid washing method and then dispersed in alcohol. Sm2Zr2O7-CNT composite powders containing different amounts of CNT were synthesized by corprecipitation method and hot-press sintering were selected to prepare the composites. The density and thermal conductivity of the samples were tested. The micro-morphology and phase structure of composites were characterized by field emission scanning electron microscope and X-ray diffraction, respectively. Based on these experiments and theoretical analyses, the influences of carbon nanotube on the micro-morphology, phase structure and thermal conductivity of Sm2Zr2O7-CNT composite were revealed. Results showed that the carbon nantube uniformly dispersed in Sm2Zr2O7 matrix and the thermal conductivity of composites varied with the different amounts of CNT. In this article, the variation of thermal conductivity can be explained by the comprehensive evaluation of Sm2Zr2O7, CNT, pore and the heterogeneous interfaces thermal resistance between matrix and additives.