Sericin has shown a great potential as a biomaterial in biomedical application due to its good hydrophilicity,reactivity and biodegradability.To solve the adherence and growth of microorganisms on sericin gel,here we prepared a polyelectrolyte film with interactive arrangement of opposite charges poly(dimethyldiallylammmonium chloride)(PDDA)and poly(acrylic acid)(PAA)coated on the surface of sericin gel via electrostatic interaction.AgNPs was then synthesized with the assistance of UV in situ on the polyelectrolyte film to endow the antibacterial activity of sericin gel.SEM revealed the polyelectrolyte film could effectively facilitate the high density growth of AgNPs as a 3-D matrix and the modification of polyelectrolyte and AgNPs did not alter the porous characteristics of sericin gel.XRD studies suggested AgNPs synthesized on polyelectrolytes film coated sericin gel had good crystal structure.DSC analysis showed AgNPs could form tight binding with polyelectrolytes film and sericin gel,and the binding may alter the melting temperature of AgNPs.Both bacterial inhibition zone and growth curve assay demonstrated AgNPs-polyelectrolytes film coated sericin gel had an excellent and long-lasting antibacterial activity.This novel sericin gel has shown great potentials in biomedical application such as wound healing.