Photocatalysis　has　been　regarded　as　an　emerging　technology　to　convert　renewable　solar　energy　to　chemical　fuels,　providing　unprecedented　opportunities　for　solving　the　deteriorating　energy　crisis　and　environmental　issues　in　the　future.　In　recent　years,　atomically　precise　gold　nanoclusters,　which　have　emerged　as　novel　light-harvesting　antennas　possessing　the　merits　of　unique　atomic　stacking　fashion,　the　quantum　confinement　effect,　enriched　catalytically　active　sites　and　a　discrete　energy　band　structure,　have　been　drawing　enormous　attention　in　diverse　fields.　Despite　the　advancement,　there　is　deficiency　of　a　systematic,　comprehensive,　and　insightful　summary　on　the　gold　nanocluster-based　photosystems　to　reinforce　our　fundamental　understanding　of　the　charge　transport　characteristics　of　metal　nanoclusters　in　photocatalysis.　Herein,　our　review　summarizes　the　latest　progress　in　gold　nanocluster　mediated　photocatalysis　and　photoelectrocatalysis　for　diverse　applications　including　non-selective　photocatalytic　organic　pollutant　mineralization,　photocatalytic　selective　organic　transformation,　photocatalytic　hydrogen　generation,　photocatalytic　CO2　reduction,　and　photoelectrochemical　(PEC)　water　splitting.　Moreover,　we　discuss　the　underlying　photocatalytic　and　PEC　mechanisms　associated　with　the　energy　band　and　electronic　structure　of　gold　nanoclusters.　Finally,　perspectives　and　challenges　of　gold　nanocluster-based　photosystems　are　outlined.　It　is　anticipated　that　our　review　could　inspire　ideas　on　how　to　smartly　utilize　atomically　precise　metal　nanoclusters　for　crafting　high-efficiency　photosystems　towards　solar　energy　conversion.