Abstract: Silver nanoparticles (AgNP) were prepared as a mixture of AgO, Ag2O and Ag from silver nitrate and hydrogen peroxide at room temperature in dark. The process of synthesis includes changing the sequence of addition for AgNO3 and H2O2 in addition to change the concentration of H2O2. The structural morphology and optical properties of silver nanoparticles (AgNPs) were characterized by X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), UV-visible absorbance and Fourier-Transform Infrared Spectroscopy (FTIR). The results showed that the change in routes of addition for materials causing produces the change in the ratios of Ag species. The highest value for Ag nanoparticles was shown for Ag2 when produces 31.25% while Ag3 consist 71.10% of AgO. The antibacterial activity for the synthesized AgNPs were shown variances when tested with bacterial Acinetobacter baumannii which shows maximum activities with Ag3.