Metal-free photocatalyst producing reactive oxygen species (ROS) is promising for photocatalysis antibacterial, but flexible-functionalized single-organic photocatalyst for photocatalysis antibacterial remains a significant challenge. Herein, we reported a g-C3.6N4/polyvinyl alcohol (PVA) hydrogel synthesized by the chemical crosslinking method. Our strategy makes solid-state g-C3.6N4 become into the flexible-functionalized membrane and achieve its photocatalysis antibacterial. The characterization of microscopic morphology and structure of g-C3.6N4/PVA reveal that the porous cavity of PVA hydrogel is uniformly filled with nanosheet-like g-C3.6N4 in the g-C3.6N4/PVA membrane, which benefits to making the porous PVA hydrogel denser and producing efficient ROS. The g-C3.6N4/PVA hydrogel shows superior photocatalytic antibacterial rate (>99%) towards Escherichia coli under visible light irradiation (λ > 420 nm) and the cytotoxicity was negligible. Theoretical calculations have confirmed that Schiff-base bonds are conducive to the rapid transfer electrons in the g-C3.6N4, leading to the C atom forming the double bond and losing fewer electrons. The flexible-functionalized g-C3.6N4/PVA hydrogel membrane exhibits great promise for application in wound disinfection.