Surface plasmonic resonance effect has been widely applied to improve oxidation activity of a photocatalyst under visible light irradiation. Palladium particles were successfully prepared, and electrostatically assembled with BiOBr in this work. Due to the differences in work function between palladium and BiOBr, a Mott-Schottky junction may be established. This junction is in favor of the separation of photogenerated charge carriers. Also, Pd particles on the surface may absorb visible-light photons and produce extra electrons to participate in the photocatalysis. The great improvement in the photocatalytic oxidation of phenol confirms the synergetic effect (SPR and Mott-Schottky junction). This work may serve as a solid evidence to confirm that surface-loaded palladium particles are capable of improving photocatalytic activity, and that electrostatic assembly may be an effective approach to load metal particles onto a surface.