The electrochemical reduction of dioxygen on the single-walled carbon nanotubes–dihexadecyl phosphate (SWNTs–DHP) film electrode has been investigated. Two well-defined dioxygen reduction peaks were observed at about −0.39 and −0.93V in 0.1M air-saturated NaOH at the SWNTs–DHP film electrode suggesting two two-electron reduction steps of dioxygen. The numbers of electron transferred and transfer coefficients in the dioxygen reduction process were calculated. The influences of some parameters on the reduction of dioxygen were examined including the concentration and amount of nanotubes, and ratio of SWNTs vs. DHP. Based on the experiment results under the conditions employed here, a possible mechanism is proposed and discussed.