The effects of protection gas (nitrogen gas) flow rate on the electrochemical capacitance of activated carbon nanotubes (CNT) have been investigated. Nitrogen gas flow rate in the process of activated CNT preparation can great affect the activated CNT electrochemical capacitance, which carries out by virtue of its effects on activated CNT BET specific surface area. When the electrochemical capacitance of activated CNT reaches its maximum, there is an optimal value to nitrogen gas flow rate. (c) 2005 Elsevier B.V. All rights reserved.