<p>Polyvinylidene fluoride (PVDF) fiber membrane was prepared through electrospinning with N, N-dimethylformamide&#xa0;(DMF) and acetone (AC) as mixed solvents as hydrophobic layer of Janus membrane. Polyacrylonitrile (PAN) fiber membrane was fabricated through electrospinning with DMF as solvent as hydrophilic layer of Janus membrane. N-Halamine antibacterial agent 1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone (MC) was added to endow the fiber membrane with antibacterial properties. PVDF@MC/PAN@MC composite fiber membrane with Janus structure was prepared by continuous electrospinning. The surface morphologies of fiber membranes were characterized by scanning electron microscopy (SEM). The water contact angles (WCAs), underwater oil contact angles (UWOCAs), pure water fluxes, separation fluxes and separation efficiencies of fiber membranes were measured. In addition, the antibacterial experiments of fiber membranes were also performed. The results showed that the prepared PVDF@MC/PAN@MC composite fiber membrane had a Janus structure with one side hydrophilic and underwater oleophobic, and the other side hydrophobic and underwater oleophobic. And the PVDF@MC/PAN@MC composite fiber membrane had certain separation performance for mud, oil–water emulsion, metal ions, and organic dyes. Furthermore, the PVDF@MC/PAN@MC composite fiber membrane had good antibacterial effect on <i>Staphylococcus aureus</i> (<i>S. aureus</i>) and <i>Escherichia coli</i> (<i>E. coli</i>).</p>