Abstract: Quaternary ammonium salts as a kind of typical antibacterial materials, possess excellent bactericidal properties. However, most quaternary ammonium salts have the defects of low plasticity and poor film forming performance. Based on this, P(BA-co-DMAEMA) was prepared by free radical polymerization with n-butyl acrylate (BA) and 2-(diethylamino) ethyl methacrylate (DMAEMA). Then, a series of acrylic P(BA-co-DMAEMA)-R (R: bromine butane (BB), bromo hexane (HB) and bromine octane (OB) ) copolymers with different length alkanes were obtained by using BB, HB, OB as quaternization agents. Finally, P(BA-co-DMAEMA)-R films were prepared by tape casting method. The chemical structures of P(BA-co-DMAEMA) and P(BA-co-DMAEMA)-R were characterized by ¹H-nuclear magnetic resonance (¹H-NMR), Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). The mechanical properties, hydrophilicity, light transmittance of P(BA-co-DMAEMA)-R films were tested by universal mechanical testing machine, contact angle tester, UV spectrophotometer. The results show that the introduction of brominated alkanes (BB, HB, OB) could effectively improve the mechanical properties, hydrophilicity, light transmittance of the films. The elongation at break of P(BA-co-DMAEMA)-R films increases with the increase of alkane chain, the surface of the films changes from hydrophilic to hydrophobic. The transmittance of P(BA-co-DMAEMA)-R films increases with the increase of alkane chain, and the maximum transmittance is over 80%. The antibacterial properties of P(BA-co-DMAEMA)-R films are assessed by agar plate colony counting assay and zone of inhibition test. When n(BA)/n(DMAEMA) = 23/77, the quaternization degree of P(BA-co-DMAEMA)-R are 58% (BB), 45% (HB) and 39% (OB), respectively. It is observed that P(BA-co-DMAEMA)-R films exhibited outstanding broad-spectrum antimicrobial activity against S. aureus and E. coli. The antimicrobial activity is based on contact-killing of P(BA-co-DMAEMA)-R film surface, without releasing bactericidal agents, as demonstrated by the zone of inhibition test. Meanwhile, P(BA-co-DMAEMA)-R films also possess excellent antifogging performance, and its preparation process is simple and controllable, which would be used in packaging materials in the future.