The effects of different activation conditions (including KOH/CNTs ratio, activation temperature, activation time and nitrogen flow rate) on the electrochemical capacitance of activated carbon nanotubes (CNTs) have been investigated. All the four factors can affect the activated CNTs' electrochemical capacitance. And the effects on the activated CNTs' electrochemical capacitance carried out by virtue of their effects on activated CNTs' BET specific surface area and graphitized degree. (c) 2005 Elsevier B.V. All rights reserved.