This study investigated different dispersed double-walled carbon nanotubes (DWCNTs) as supports for depositing Pt nanoparticles. Homogenously dispersed Pt particles with sizes of approximately 2.08 nm were obtained on DWCNT surfaces. The size and the dispersion state of the Pt particles on the DWCNT support exhibit stronger hydrogen desorption/adsorption peaks and higher electrochemical activity (electric current density is 0.022 A·cm?2 and electrochemical specific surface area is 86.38 m2·g-1) compared to the other Pt/DWCNT catalysts. Further analysis shows that the concentration of the support in the suspension significantly affects the size and the uniformity of the generated Pt particles. The Pt particles of the size and the state on the supports can realize a Pt catalyst with high electrochemical activity and low cost.