Abstract: Gold nanoparticles can absorb ultraviolet or visible light to activate reagent molecules under mild condition，and this promote the reactions and improve the conversion of reactants and selectivity of products. So it became hot topics of the recent resrarch. In this paper，the photocatalytic reaction mechanism of gold catalyst，namely，the charge dipole caused by the surface plasma resonance exited by photons inducing the electron-philic or nucleophilic reaction，was reviewed，and the mechanism of gold nanoparticles supported on the semiconductor material TiO2. And the progress and applications of gold photocatalysts in degradation of dyes and pollutants，decomposition of ozone，reduction of nitrocompound，selective oxidation and hydrogen production were introduced. And the future research progress of this new photocatalysts is prospected.

Key words: gold catalyst, photocatalysis, surface plasma resonance