Roles of ultrasound on the hydroxyl radical generation from water electrolysis were examined in this work. Results indicated that the ultrasound could not only strengthen the mass transfer of liquid phase, but also could improve the electron gain and loss for hydroxyl ion, and thus improve the hydroxyl radical generation. Results from ESR signal indicated that, ultrasonic strengthened hydroxyl radical formation from water electrolysis in whatever in alkaline or acidic solution. Ultrasound improved the equilibrium potential and current of OER, indicating that ultrasound inhibited the thermodynamics conditions in OER. Ultrasound inhibited the oxygen gas release, and thus resulting in the increase in the amount of hydroxyl radicals. The R-ct of OER increased with ultrasound addition, while the R-s for water electrolysis decreased. Whatever platinum (Pt) or nickel (Ni) electrode, bauxite electrolysis desulfurization all were improved by ultrasound, and the desulfurization of Ni under ultrasound was higher than Pt without ultrasound. That is, electrolysis desulfurization with Ni electrode in presence of ultrasound could replace electrolysis desulfurization with Pt electrode in absence of ultrasound. (C) 2018 The Electrochemical Society.