Nanometer ZnO is a common optical material which can be processed into an antibacterial packaging material while compounding with other materials. According to GB/T 21510—2008 of Detection Method for Antibacterial Properties of Nanometer Inorganic Material, adopting SiO2 for controlled trials, the antibacterial properties of nanometer ZnO was tested against Escherichia coli and staphylococcus aureus strains. The qualitative research was conducted using bacteriostatic circle method. The result showed that nanometer ZnO performed well in antibacterial activity against the tested bacteria. The minimum inhibitory concentration of the nanometer ZnO was initially determined as 0.312 5% and 0.625% respectively for the tested bacteria. Nanometer ZnO was highly sensitive to these two kinds of tested bacteria with the antibacterial circle diameter greater than 15 mm in both cases.