Core-shell type silica-polymer nanocomposites were synthesized by grafting 2-hydroxyethyl methacrylate (HEMA) from the surface of silica nanoparticles (SiO2 NPs) via surface-initiated single-electron transfer mediated living radical polymerization (SET-LRP). Firstly, end capping was achieved by an Ugi four-component reaction of (3-aminopropyl) trimethoxysilane, 2-bromo-2-methylpropionic acid, benzaldehyde, and 1-pentyl isocyanide to yield SiO2-Br macro-initiator for SET-LRP. Then, 2-hydroxyethyl methacrylate (HEMA) was polymerized from the surface of SiO2-Br in the presence of copper wire and PMDTA as a catalyst system, resulting in the formation of silica-polymer (SiO2/PHEMA) core-shell nanoparticles. The SiO2/PHEMA composites were characterized by FT-IR, XPS, TGA, and XRD analysis. Furthermore, the hydroxyl groups of SiO2/PHEMA could be converted to carboxyl groups by esterification reaction with succinic anhydride, which gave higher loading capacity for silver ion (Ag+). The coverage of SiO2 NPs by a polymer layer containing Ag NPs was confirmed by TEM images revealing the core-shell structure.