As　a　new　member　of　carbon　material　family,　carbon　quantum　dots　(CQDs)　have　attracted　tremendous　attentions　for　their　potentials　in　the　heterogeneous　photocatalysis　applications.　Due　to　the　unique　microstructure　and　optical　properties,　the　roles　of　CQDs　played　in　the　CQDs-based　photocatalytic　systems　have　been　found　to　be　diverse　with　the　continuous　researches　in　this　regard.　Herein,　we　provide　a　concise　minireview　to　elaborate　the　multifarious　roles　of　CQDs　in　photocatalysis,　including　photoelectron　mediator　and　acceptor,　photosensitizer,　photocatalyst,　reducing　agent　for　metal　salt,　enhancing　adsorption　capacity　and　spectral　converter.　In　addition,　the　perspectives　on　future　research　trends　and　challenges　are　proposed,　which　are　anticipated　to　stimulate　further　research　into　this　promising　field　on　designing　a　variety　of　efficient　CQDs-based　photocatalysts　for　solar　energy　conversion.　©　2016　Science　Press