The　development　of　catalyst　for　photocatalytic　hydrogen　sulfide　(H2S)　oxidation　with　excellent　efficiency　and　regeneration　properties　is　a　significant　challenge.　Herein,　the　pyridine　units　as　bifunctional　sites　are　incorporated　in　covalent　polymers　(CPs)　by　C-N　coupling　reaction,　which　exhibit　photocatalytic　H2S　selective　oxidation　to　sulfur　conversion　(95　%)　under　visible　light　in　a　continuous　flow　system,　more　than　twice　that　of　the　pristine　sample　(40　%).　Meanwhile,　the　photocatalytic　H2S　conversion　rate　had　a　linear　function　relationship　with　pyridinic　N　content,　demonstrating　the　substantial　role　of　pyridine　in　photocatalytic　H2S　oxidation　process.　According　to　experimental　results,　the　pyridine　unit　not　only　acted　as　the　structural　base　site　to　improve　the　H2S　chemisorption,　but　also　served　as　electron　withdrawing　unit　to　construct　electron　donor-acceptor　(D-A)　structure　with　benzene,　which　optimized　the　light　absorption,　charge　separation　and　migration.　In　addition,　series　in-situ　measurements　and　electron　density　difference　simulations　revealed　the　significant　role　of　electron　D-A　structure　in　H2S　adsorption　and　activation　process.　By　exploring　the　effect　of　pyridine　unit　in　CPs　on　H2S　conversion　process,　this　work　provides　a　new　idea　for　the　subsequent　study　of　photocatalytic　H2S　oxidation.