A　sequential　cation-exchanging　method　is　developed　at　the　first　time　to　synthesize　cation　doped　g-C　3　N　4　.The　eutectic　molten　salt　(LiCl:KCl:NaCl=1:1:1　in　weight)　and　melamine　are　firstly　mixed　in　the　ratio　of　10:1　and　then　dissolved　in　the　distilled　water.Then　different　amounts　of　MnCl　2　solution　is　added　as　a　doping　precursor,with　concentration　of　manganese　being　0%,0.3%,0.5%　and　0.7%,respectively.After　water　in　the　solution　is　entirely　evaporated　out　by　a　rotary　evaporator,the　remaining　powder　is　put　into　an　alumina　crucible　with　a　cover,and　then　heated　at　520℃　for　4　h　to　get　multi-elements　doped　nanotubes.The　obtained　nanotubes　are　treated　with　1　M　HCl　solution　for　3　h,which　removing　Na　+　,K　+　and　Li　+　.The　powder　sample　is　finally　calcined　at　400℃　for　2　h　again,removing　Cl　+　and　H　+　and　finally　get　a　Mn　doped　g-C　3　N　4　sample.This　preparation　method　solves　the　problem　that　the　conventional　ion　doped　carbon　nitride　material　has　a　small　specific　surface　area　and　uncontrollable　morphology.The　morphology,phase　structure,pore　structure,light　absorption　and　carrier　separation　efficiency　of　the　obtained　samples　are　detected　by　SEM,XRD,BET,UV-Vis,FT-IR　and　PL.The　photocatalytic　hydrogen　production　performances　of　samples　are　evaluated　under　visible　light.　©　2018,　China　National　Chemical　Information　Center.　All　right　reserved.