A new collolidal silver (Ag) system is present in which a fine colloidal Ag is in situ deposited onto functionalized porous poly(ethylene glycol dimethacrylate) (poly (EGDMA)) microspheres. The effectiveness of Ag deposition was investigated considering the surface characteristics of poly (EGDMA) microspheres, The result reported in this study illustrates that the control of surface area and surface functionality (in this study, a hydroxyl group) of poly (EGDMA) microspheres is an important factor that determines practically the degree of deposition of colloidal Ag. The x-ray analysis showed that Ag nanoparticles were dispersed evenly inner and outer surfaces and has a face center cubic(fcc) phase. In the preservation test, the Ag-containing poly (EGDMA) microspheres had a powerful anti-bacterial performance, showing a high potential for a new preservative.