Quaternized cellulose (YM) was homogeneously synthesized by grafting 3-chloro-2-hydroxy-propyldodecyldimethylammonium groups onto cellulose molecules in a NaOH/urea aqueous solution. YM was blended with a poly(vinyl alcohol) (PVA) matrix to prepare composite films via co-regeneration from the alkaline solution. The PVA film and the blend films were characterized by Fourier transform infrared spectroscopy, X-ray diffraction measurements, thermogravimetric analysis, and scanning electron microscopy. Mechanical properties, water vapor barrier properties, light transmission, and antibacterial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria were also evaluated. The results reveal that PVA and YM in the composite films interacted by hydrogen bonding. Compared with pure PVA film, the PVA/YM blend films had higher tensile strength, higher thermostability, lower water permeability, and especially, higher antibacterial activity. The blend films exhibited good UV-shielding performance. Our study demonstrates a simple and efficient method for preparing a functional, environment-friendly composite film. (C) 2016 Elsevier B.V. All rights reserved.