Abstract: Based on electrohydrodynamics(EHD)enhancement of boiling heat transfer outside a tube and condensation heat transfer inside a tube in high voltage DC electric field, three coaxial cylindrical featured electrodes were presented.These three featured electrodes had minimum electric field strength,minimum electric field force and minimum work consumption, respectively，and the latter two electrodes were derived by the authors for the first time.The geometric characteristics of the electrodes were analyzed and the results showed that the diameter of the electrode played an important role in EHD enhancement of phase-change heat transfer.