In this paper, zinc oxide (ZnO), copper oxide (CuO), and titanium oxide (TiO2) nanoparticles were prepared using sol-gel method. The structural properties of these nanoparticles were characterized using X-Ray Diraction (XRD) and Transmission Electron Microscopy (TEM). SEM images revealed that the average sizes of zinc oxide, copper oxide, and titanium oxide nanoparticles are about 37 nm, 86 nm, and 50 nm, respectively. Then, nanocomposites of metal oxide were produced by Polyvinyl Alcohol (PVA). The antibacterial activities of zinc oxide, copper oxide, and titanium oxide nanocomposites against human pathogenic bacteria, mainly Escherichia coli HB101 (gram-negative), have been studied using drop test during the time periods of 15 minutes, 30 minutes, 1 hour, 2 hours, 12 hours, and 24 hours of generated reviews. According to the results obtained with the nanocomposite, zinc oxide nanoparticles exhibit the highest antibacterial properties.