[en] A simple and cost-effective method was introduced to fabricate a highly stable Ag-nanoparticle (AgNPs) decorated mesoporous poly(acrylic acid) (PAA) nanofiber membrane. Sol-gel/electrospinning method was applied for the membrane fabrication followed by template extraction. Neither high-temperature thermal treatment nor hazardous solvents or reducing agents were used, which is a typical environmental friendly approach. Instead, PAA was provided as seeding sites for stabilizing and reducing Ag ions. The TEM images show that well-dispersed Ag nanoparticles (d = ∼10 nm) are formed by in situ/self-assembly on the surface of PAA nanofiber. The mesoporous nanofiber membrane has a surface area and pore size of about 405 m² g⁻¹ and 3.50 nm, respectively. The membrane antibacterial performance was examined in the dark, and a complete Escherichia coli inactivation was achieved within 30 min. Due to the 1D characteristic of the nanofiber, it was convenient for recovery and reuse. Such synthesis strategy can be extended to other particle systems for various applications in catalysis, energy, sensing, photonic and biomedical applications. (paper)