Modifying　the　structure　of　a　photocatalyst　to　tailor　its　electronic　and　physicochemical　properties　is　an　effective　approach　for　efficient　photocatalysis.　Herein,　we　demonstrate　that　co-doping　non-metal　(S)　and　metal　(K)　atoms　into　graphitic　carbon　nitride　(g-C3N4)　provides　excellent　visible-light　photocatalytic　hydrogen　production　activity　of　8.78　mmol　g(-1)　h(-1),　which　is　98　times　higher　than　that　of　pristine　g-C3N4　(0.09　mmol　g(-1)　h(-1)).　The　apparent　quantum　efficiency　of　the　S+K-co-doped　g-C3N4　reaches　70　%　at　420　nm.　This　outstanding　photocatalytic　performance　attributed　to　an　increased　specific　surface　area　from　6.78　to　74.23　cm(3)　g(-1),　which　reduced　the　recombination　of　photogenerated　charge　carriers　and　enhanced　conductivity.　Various　characterizations　are　undertaken　to　elucidate　the　S+K-co-doped　g-C3N4　photocatalytic　mechanism.　Our　work　not　only　demonstrates　a　facile,　eco-friendly　and　scalable　strategy　for　the　synthesis　of　S+K-co-doped　g-C3N4　photocatalysts,　but　also　opens　a　new　avenue　for　the　design　of　co-doped　photocatalysts.