Carbon nanotubes (CNTs) have been much attractive additives of various matrix composites due to their extraodrinary mechanical, electric, thermal properties, one dimensional shape and small size. In this research, the thermal properties of CNTs reinforced Al-Cu matrix nanocomposites were investigated. CNT/Al-Cu nanocomposites with 0-4 vol.% of CNTs were prepared by mixing of CNT/Cu powders and Al powders by high energy ball mill process followed by spark plasma sintering. During the high energy ball milling and sintering, Cu particles are alloyed in the Al to form Al-Cu alloy matrix. The CNT/Al-Cu nanocmposites show a microstructure of homogeneous dispersion of CNTs in the Al-Cu matrix. Despite high thermal conductivity of CNTs, the thermal conductivity of CNT/Al-Cu nanocomposites decreased as increasing the content of CNTs because of the interface thermal resistance between CNTs and Al-Cu matrix. The coefficient of thermal expansion (CTE) also decreased due to homogeneous dispersion and low CTE value of CNTs