Hexagonal　boron　nitride　(h-BN),　an　emerging　two-dimensional　material,　has　attracted　great　attention　in　various　fields.　However,　due　to　its　large　band　gap　(ca.　6　eV),　h-BN　has　not　yet　been　exploited　as　a　photocatalyst.　Here,　we　demonstrate　a　porous　h-BN　sheets　with　rich　hydroxyl　(-OH)　and　secondary　amino　(-NH)　groups,　which　can　effectively　decrease　the　band　gap　of　h-BN.　Porous　h-BN　sheets　were　synthesized　via　combustion　of　boron　acid　and　urea　at　high　temperature　under　nitrogen　atmosphere.　The　as-obtained　porous　h-BN　has　a　narrower　band　gap　and　a　higher　photocatalytic　activity　on　hydrogen　evolution　than　commercial　h-BN.　To　further　understand　this　photocatalytic　performance,　we　investigated　the　groups,　structure,　and　related　optical　and　electrochemical　properties　for　both　porous　and　commercial　h-BN.　This　work　holds　promise　for　h-BN　to　be　used　in　the　photocatalysis　field.