： A novel antibacterial polyacrylonitrile (PAN) membrane covalently 3 immobilized with lysozyme was prepared. First, the virginal PAN membranes were 4 prepared via the classic immersion precipitation method. After modification with 5 NaOH, HCl, Ethylenediamine (EDA), lysozyme was covalently immobilized onto the 6 surface of PAN membranes by glutaraldehyde. The chemical compositions of virginal 7 and modified membranes were characterized by Fourier Transform Infrared 8 spectroscopy (FT-IR) and Energy Dispersion X-ray (EDX). The morphology and 9 performance of the immobilized membranes were characterized by Scanning 10 Electronic Microscopy (SEM), filtration performance measurement, the amount of the 11 bonded lysozyme, lysozyme activity measurement and flow cytometry method. The 12 antibacterial tests confirmed that the immobilized lysozyme membrane displayed an 13 excellent antibacterial performance against staphylococcus aureus (S. aureus). 14 15 17 onto the surface of PAN membranes by glutaraldehyde. Morphologies, structures, 18 water flux and antimicrobial efficacies (against S. aureus) of the membranes were 19 investigated. The result indicated the activity of immobilized lysozyme was relatively 20 high and could effectively prevent formation of biofilms. The highly antibacterial 21 membranes have potential application in water treatment and food manufacturing.