Photo-induced　atom　transfer　radical　polymerization　(ATRP)　becomes　a　significant　method　for　preparing　well-defined　polymers　with　pre-designable　molecular　weight　and　narrow　molecular　weight　dispersity　(M-w/M-n).　Herein,　a　fully-pi　covalent　organic　framework　(COF)　was　constructed　and　served　as　heterogeneous　photocatalyst　for　photo-induced　ATRP　under　LED　irradiation.　TCPB-DMTA-COF,　which　was　constructed　by　Knoevenagel　polycondensation　of　1,3,5-tris(4-cynomethylphenyl)benzene　(TCPB)　and　2,　5-Dimethoxy-terephthalaldehyde　(DMTA)　and　exhibited　remarkable　performance　in　mediating　photo-induced　ATRP　of　methyl　methacrylates　with　the　assist　of　ppm-level　concentration　of　Cu-II　under　LED　irradiation,　producing　polymers　with　high　chain-fidelity　and　low　value　of　M-w/M-n　(1.10-1.35).　The　switch　＂on/off＂　experiment　exhibits　excellent　temporal　and　spatial　control　toward　polymerization　system.　Compared　with　TCPB-DMTA-CMP,　the　high　crystallinity　and　stability　of　TCPB-DMTA-COF　endows　high　monomer　conversion　and　good　recyclability　performance　for　photo-induced　ATRP.　These　results　suggest　COF　can　be　served　as　a　promising　artificial　photocatalyst　for　photo-induced　ATRP.