Core–shell silver/mesoporous-silica spheres (Ag@mSiO₂) were synthesised via a hydrothermal route and incorporated into poly (vinylidene fluoride) (PVDF) to fabricate antibacterial dual-layer ultrafiltration membranes by co-casting followed by phase inversion. Membrane morphology and composition were characterised using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), whereas hydraulic performance, mechanical strength, fouling resistance and antibacterial activity were evaluated through pure-water permeation, cyclic filtration and bacteriostatic assays. Incorporation of Ag@mSiO₂ progressively increased the water flux while maintaining a bovine serum albumin (BSA) rejection above 91%. At an Ag@mSiO₂ loading of 0.3wt%, the pure-water flux rose from 373 to 536 L/(m²·h) and the flux-recovery ratio improved from 57.9% to 82.5%, indicating a substantial enhancement in antifouling performance. Moreover, higher nanoparticle contents produced a pronounced, dose-dependent antibacterial effect against Escherichia coli, confirming the excellent bioactivity of the hybrid membranes.