controllable in situ synthesis of silver nanoparticles on multilayered filmcoated silk fibers for antibacterial application layerbylayer lbl assembly is a versatile technique for the preparation of multilayered polymeric films however fabrication of lbl polymetic film on silk for the in situ growth of highdensity silver nanoparticles agnps has not been realized herein polyacrylic acid paapolydimethyldiallylammonium chloride pdda multilayers are constructed on silk via the lbl approach subsequently serving as a 3dimensional matrix for in situ synthesis of agnps after 8 rounds of lbl assembly the silk is fully covered with a layer of polymeric film agnps with good crystalline structures could be insitu generated in the silkcoated multilayers and their amount could be tailored by adjusting the bilayer numbers the asprepared silk could effectively kill the existing bacteria and inhibit the bacterial growth demonstrating the antimicrobial activity moreover the release of ag from the modified silk can last for 120 h rendering the modified silk sustainable antimicrobial activity this work may provide a novel method to prepare agnpsfunctionalized antimicrobial silk for potential applications in textile industry