Abstract: The raw Al2O3 particles are 200 nm in average diameter. Chemical deposition of Ag was carried out taking ammonia-based solution as bath in which the silver nitrate is primary component. In the reaction process such parameters as the concentration of reducing agent, reaction time and others were optimized in order to clad uniformly all of Al2O3 particles. The result show that all Ag-Al2O3 composite particles are of core-shell structure, of which the shell is composed of amorphous Ag and crystal Ag particles and their sizes are 5 nm and 10 nm respectively. The microstructure of Ag-cladding Al2O3 powder synthesized via silver chemical process was investigated by XRD, TEM and EDS techniques.