Photocatalysis　clean　hydrogen　production　is　a　modern　technology　for　simultaneously　addressing　and　solving　energy　and　environmental　issues,　of　which　the　most　critical　part　is　to　develop　a　highly　efficient　photocatalyst.　In　this　work,　we　rationally　designed　and　synthesized　a　metal-free　2D/2D　boron/g-C3N4　nanosheet　heterojunction　(B-CN)　through　an　electrostatic　self　assembly　thermal　induction　combined　with　ultrasound-assisted　technology.　The　optimized　photocatalyst　3.0B-CN　possesses　a　hydrogen　generation　rate　35　times　that　of　g-C3N4,　which　provided　an　impressive　H-2　evolution　photocatalytic　activity.　The　tight　heterojunction　architecture　via　the　coupling　of　two-dimensional　boron　nanosheets　and　g-C3N4　nanosheets　realizes　the　enhanced　visible　light　absorption,　the　increasing　carrier　concentration,　and　the　rapid　transfer　of　interfacial　charge　and　thus　hinders　the　electron-hole　recombination.　The　coupling　of　two　2D　metal-free　nanosheet　materials　for　constructing　a　2D/2D　layered　heterojunction　in　our　work　offers　pioneering　tactics　for　the　design　and　synthesis　of　green　nonmetal　2D　photocatalytic　HER　materials　in　the　future.