Few-layer　graphitic　carbon　nitride　(g-C3N4)　nanosheets　were　fabricated　and　utilized　as　a　saturable　absorber　for　mode-locking　in　an　Er-doped　fiber　laser　with　net　normal　dispersion.　The　g-C3N4/polyvinyl　alcohol　(PVA)　hybrid-film-based　saturable　absorber　has　a　modulation　depth　of　4.01%　and　a　saturation　intensity　of　7.5　MW/cm(2).　By　integrating　g-C3N4-PVA　mode-locker　into　the　laser　cavity,　a　mode-locked　operation　could　be　obtained.　The　achieved　mode-locking　pulse　centered　at　1530.3　nm　has　a　pulse　width　of　530　ps.　Its　repetition　rate　is　40.8　MHz,　and　the　corresponding　signal-to-noise　ratio　is　about　55　dB.