A rapid preparation of nanomaterial of noble metal (Silver) via chemical reduction is presented. Silver nitrate (oxidizing), glucose (reducing) and corn starch was the capping agents. Corn starch stabilized Silver Nanoparticles (AgNPs) synthesized rapidly in aqueous system via the assistance of microwave irradiation had its Surface Plasmon Resonance (SPR) monitored by a UV-Visible Spectrophotometer and peaked at 400nm. Further characterization was by FT-IR and TEM/ SAED. Self-assembly of starch-capped silver nanoparticles gave a mirror-like glassy film surface on drying. According to the FT-IR spectroscopy, AgNPs revealed the shifting of N-H and O-H of starch still exists. TEM gave average particle size of 7nm. Result also showed that AgNPs can inhibit the growth of mold (A. niger). Method is reliable, ecofriendly, cheap and evident by the properties of the nanoparticles obtained.