We investigated an effective pretreatment method for a polycrystalline gold film surface on which an ordered self-assembled monolayer (SAM) could form. The wetting properties of the SAM surface determined by the hysteresis between advancing and receding contact angles against water and hexadecane revealed that the ordered SAM was formed on the gold surface pretreated with a combination of UV/ozone exposure and ethanol rinsing prior to SAM formation. The change in optical properties of the gold film surface was observed by surface plasmon spectroscopy (SPS), indicating that pure ethanol rinsing makes the gold surface smooth by removing small gold grains oxidized by UV/ozone exposure.