Silica particle was deposited with Ag nanoparticles to achieve hybrid structure. First, silica nanoparticles were synthesized according to the well- known Stober method by hydrolysis and condensation of TEOS in a mixture of ethanol with water, using ammonia as catalyst to initiate the reaction. These SiO2 nanoparticles were dried at 100 degrees C. We measured the size of these nanoparticles with transmission electron microscopy ( TEM). Second, Ag-SiO2 nanoparticles were synthesized by reaction with AgNO3 and SiO2 nanoparticles at room temperature for 12 hrs. Results show silica nanoparticles of about 110nm size deposited with Ag nanoparticles. Ag-SiO2 nanoparticles were investigated with TEM images, energy dispersive X- ray analysis ( EDX) spectrum. The antibiotic property was examined with disk plate method.