Abstract: Effects of sliding speed and normal load on friction behaviors of ZrO2 ball/stainless steel disc pairs Immersed in a sodium laurel sulfate solution were experimentally investigated with a ball-on-disc tribotester under three different voltage control modes,i.e.positive voltage, negative voltage and open circuit. The experiment results showed that the friction coefficient decreased with the increase in sliding speed in the cases of the positive voltage and open circuit control modes, but kept a lower value in the case of the negative voltage control mode. The mechanism of the friction behaviors was analyzed based on the differences in adsorption of the anionic laurel sulfate ions on the rubbing surfaces under the 3 different external voltage conditions.