Crystalline　covalent　organic　frameworks　(COFs)　are　porous　polymeric　semiconductors　with　network　topologies,　which　are　built　from　the　integration　of　selected　organic　blocks　with　covalent　bond　linkages.　They　have　shown　great　promise　for　artificial　photosynthesis,　owing　to　broad　light　harvesting,　high　crystallinity,　and　high　carrier　mobility.　This　Minireview　introduces　state-of-the-art　COF　photocatalysts　based　on　different　linkages　and　discusses　the　origin　of　photocatalytic　activities　for　hydrogen　evolution.　Three　typical　COF　photocatalysts,　with　linkages　including　imine　(-C=N-),　beta-ketoenamine　(O=C-C=C-NH-),　and　vinylene　(-C=C-),　are　discussed　with　a　particular　focus　on　the　advancements　in　synthetic　methodologies　and　structural　design,　as　well　as　photoelectronic　properties　that　are　relevant　to　photocatalytic　performance.　The　Minireview　is　expected　to　elucidate　their　structure-property　relationships　and　the　way　to　design　photoactive　COFs　with　enhanced　performances.