Silver thin film of 5 nm thicknesses was evaporated on glass and stainless steel substrates and annealed at 300 degrees C for one hour. Then these samples were characterized by using X-ray diffraction method (XRD), Scanning Electron Microscopy (SEM), UV-VIS spectroscopy, and subjected to anti-microbial resistance test. XRD analysis showed as deposited silver thin film coated on glass substrate and stainless steel substrates have amorphous nature. The annealed Ag thin film coated on glass and stainless steel substrates showed crystallinity with silver phase and their crystalline size were in the range of 17-45 nm. SEM image indicates that formation of silver nanoparticles with spherical morphology after annealing on the glass substrate. But there is no nanoparticle formation was observed on annealed steel substrates. The anti microbial resistance test was done against E.Coli and that microbial growth was observed after 24 and 48 hrs. The results displayed annealed Ag thin film coated on glass substrate has moderate microbial resistance till 24 hrs due the formation of silver nanoparticles.