Seeking　efficient　visible-light-driven　photocatalysts　for　water　splitting　to　produce　H2　has　attracted　much　attention.　Chemical　doping　is　an　effective　strategy　to　enhance　photocatalytic　performance.　Herein,　we　reported　phosphorus-doped　covalent　triazine-based　frameworks　(CTFs)　for　photocatalytic　H2　evolution.　Phosphorus-doped　CTFs　were　fabricated　by　a　facile　thermal　treatment　using　easily　available　red　phosphorus　as　the　external　phosphorus　species.　The　introduction　of　phosphorus　atoms　into　the　frameworks　modified　the　optical　and　electronic　property　of　CTFs,　thus　promoting　the　generation,　separation,　and　migration　of　photoinduced　electron-hole　pairs.　Consequently,　the　photocatalytic　H2-production　efficiency　of　phosphorus-doped　CTFs　was　greatly　improved,　which　was　4.5,　3.9,　and　1.8　times　as　high　as　that　of　undoped　CTFs　and　phosphorus-doped　g-C3N4　calcined　from　melamine　and　urea,　respectively.　©　2018　American　Chemical　Society.