Graphitic　carbon　nitride　(g-C3N4)　photocatalysis　for　water　splitting　is　harvested　as　a　fascinating　way　for　addressing　the　global　energy　crisis.　At　present,　numerous　research　subjects　have　been　achieved　to　design　and　develop　g-C3N4　photocatalysis,　and　the　photocatalytic　system　still　suffers　from　low　efficiency　that　is　far　from　practical　applications.　Here,　there　is　an　inspiring　review　on　the　latest　progress　of　the　doping　strategies　to　modify　g-C3N4　for　enhancing　the　efficiency　of　photocatalytic　water　splitting,　including　non-metal　doping,　metal　doping,　and　molecular　doping.　Finally,　the　review　concludes　a　summary　and　highlights　some　perspectives　on　the　challenges　and　future　research　of　g-C3N4　photocatalysts.