Carbon nanotubes (CNTs) have high Young’s modulus, low density, and excellent electrical and thermal properties, which make them ideal fillers for polymer composites. Homogeneous dispersion of CNTs in a polymer matrix plays a crucial role in the preparation of polymer composites based on interfacial interactions between CNTs and the polymer matrix. The addition of a small amount of CNTs strongly improves the electrical, thermal and mechanical properties of the composites. This paper aims to review the processing technology and improvement of properties of CNT-reinforced polymer composites. Key words: carbon nanotubes, electrical properties, thermal properties, mechanical properties, polymer composites