Display omitted •Chitosan/poly(vinyl alcohol)/graphene oxide composite nanofiber membranes were prepared and characterized.•Contact angle decreased significantly via the addition of graphene oxide.•Composite nanofiber membranes showed good antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. In this paper, chitosan (CS)/poly (vinyl alcohol) (PVA)/graphene oxide (GO) composite nanofibrous membranes were prepared via electrospinning. Such nanofibrous membranes have been characterized and investigated for their morphological, structural, thermal stability, hydrophilic and antibacterial properties. SEM images showed that the uniform and defect-free nanofibers were obtained and GO sheets, shaping spindle and spherical, were partially embedded into nanofibers. FTIR, XRD, DSC and TGA indicated the good compatibility between CS and PVA. There were strong intermolecular hydrogen bonds between the chitosan and PVA molecules. Contact angle measurement indicated that while increasing the content of GO, the distance between fibers increased and water drop showed wetting state on the surface of nanofibrous membranes. As a result, the contact angle decreased significantly. Meanwhile, good antibacterial activity of the prepared nanofibrous membranes were exhibited against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus.