Abstract: This paper gives a brief introduction to the recent progress of carbon nanotube (CNT) technologies, including their synthesis and production, molecular structures, unique properties and the potential applications in varied areas. Specifically, the main focus will be on CNT-reinforced polymer composites, and some technical issues and key research achievements in the area of nanotube reinforced composites for aerospace applications are discussed. Although carbon nanotube composites are very promising in aerospace applications, much R&D work for some key technical issues is necessary before the full potential of CNT-reinforced composites can be realized and implemented.