The　increasing　energy　crisis　and　the　worsening　global　climate　caused　by　the　excessive　utilization　of　fossil　fuel　have　boosted　tremendous　research　activities　about　CO　2　capture,　storage　and　utilization.　Artificial　photosynthesis　that　uses　solar　light　energy　to　convert　CO　2　to　form　value-added　and　renewable　fuels　such　as　methane　or　methanol　has　been　consistently　drawing　increasing　attention.　It　is　like　killing　two　birds　with　one　stone　since　it　can　not　only　reduce　the　greenhouse　effects　caused　by　CO　2　emission　but　also　produce　value　added　chemicals　for　alternative　energy　supplying.　This　review　provides　a　brief　introduction　about　the　basic　principles　of　artificial　photosynthesis　of　CO　2　and　the　progress　made　in　exploring　more　efficient　photocatalysts　from　the　viewpoint　of　light　harvesting　and　photogenerated　charge　carriers　boosting.　Moreover,　the　undergoing　mechanisms　of　CO　2　photoreduction　are　discussed　with　selected　examples,　in　terms　of　adsorption　of　reactants,　CO　2　activation　as　well　as　the　possible　reaction　pathways.　Finally,　perspectives　on　future　research　directions　and　open　issues　in　CO　2　photoreduction　are　outlined.　©　2015　Elsevier　B.V.　All　rights　reserved.