Carbon　dots　(Cdots)　has　been　proved　to　possess　the　catalytic　decomposition　of　H2O2　in　the　photocatalytic　system.　It　is　a　potential　photo-Fenton　catalyst.　Since　multiple　emissive　Cdots　have　different　light　response　range.　There　is　rarely　investigation　on　the　performance　of　Cdots　based　photo-Fenton　on　the　light　wavelength.　Herein,　blue,　green　and　red　emissive　carbon　dots　were　synthesized　from　the　different　ratio　of　o-phenylenediamine　and　catechol　by　the　solvothermal　method.　They　exhibit　different　light　adsorption　range　from　UV　to　visible　light.　Furthermore,　the　photo-Fenton　reactivity　of　Cdots　was　studied　for　catalyzing　the　decomposition　of　H2O2　to　generate　free　hydroxyl　radicals　and　consequently　applying　for　the　removal　of　methyl　blue.　The　results　exhibit　that　Cdots　with　the　broader　light　adsorption　rang　possess　the　stronger　catalytic　activity　for　the　photo-Fenton　reaction.　The　H2O2　decomposition　rate　of　red　emissive　Cdots　is　0.074　min(-1),　which　is　2.64　and　1.46　times　than　the　blue　and　green　emissive　Cdots,　respectively.　And　the　radical　detection　results　confirm　that　the　photo-Fenton　happens　in　the　reaction.　In　addition,　the　Cdots　photo-Fenton　can　be　carried　out　in　the　broad　pH　range　from　acidic　to　basic　solution,　which　has　a　great　potential　to　treat　wastewater　in　the　neutral　system.　(C)　2021　Chinese　Chemical　Society　and　Institute　of　Materia　Medica,　Chinese　Academy　of　Medical　Sciences.　Published　by　Elsevier　B.V.　All　rights　reserved.