Carbon　nitride,　regarded　as　a　promising,　environmentally　friendly　and　sustainable　photocatalyst　for　solar　hydrogen　generation,　has　shown　a　gradual　improvement　of　photocatalytic　activity　with　an　apparent　quantum　yield　up　to　60%.　However,　it　is　still　challenging　to　achieve　flexible,　efficient　and　scalable　carbon　nitride　solar　hydrogen　evolution　devices,　limiting　its　practical　application.　Herein　we　report　a　visible-light-driven　double-side　hydrogen　evolution　nanopaper　that　is　highly　porous,　crystalline　and　chemically　stable.　The　nanopaper　was　fabricated　via　vacuum　filtration　of　electrostatically　self-assembled　carbon　nitride　and　nanocellulose.　This　nanopaper　shows　excellent　mechanical　properties　with　tensile　strength　of　18.5　MPa　and　Young＇s　modulus　of　414　MPa,　a　high　hydrogen　evolution　rate　of　3.9　mmol　g(-1)　h(-1)　(corresponding　to　6.5　mu　mol　cm(-2)　h(-1)),　and　remarkable　photostability　over　32-h　photocatalytic　tests.