By use of octadecanethiol adsorption onto silver in aqueous micellar solution, self-assembled monolayers (SAMs), which were dense, smooth and hydrophobic, were obtained. EMPA and XPS tests show that the surfactants including CTAB, TX-100, PLE and PE6400, as the dispersants of octadecanethiol, play a role of transfer during the self-assembling process; they do not take part in monolayer formation themselves but they can influence the thickness and tilt angle of SAMs. Ag2O on the surface is reduced by H-S bond of the thiol, and Ag-S-C18H37 is formed at the same time.