Photoinduced electron-transfer system of anthracene-N,N-di-ethylaniline (DEA) was studied in the oil in water (O/W) mi-croemulsions formed by SDS (sodium dodecyl sulfate),BA (benzyl alcohol) and H2O.The time-resolved fluorescence study showed that the fluorescence quenching of the excited anthracene by DEA occurs at the interface of the O/W mi-croemulsions.Besides as the quencher of the excited anthracene,N,N-diethylaniline could act as a cosurfactant to change the structures of the microemulsions,just as BA did.The quenching rate constants for the different structures of the system were determined. Photoinduced electron-transfer system of anthracene-N, N-di-ethylaniline (DEA) was studied in the oil in water (O / W) mi- croemulsions formed by SDS (sodium dodecyl sulfate), BA (benzyl alcohol) The time-resolved fluorescence study showed that the fluorescence quenching of the excited anthracene by DEA occurs at the interface of the O / W mi-croemulsions. Besides as the quencher of the excited anthracene, N, N-diethylaniline could act as a cosurfactant to change the structures of the microemulsions, just as BA did. quenching rate constants for the different structures of the system were determined.