. Zn2+/diatomite antibacterial agent was prepared by diatomite loading and solidifying Zn2+ in its holes through ion exchange and heat treatment at high temperature. Influencing factors on its preparation were discussed. Antibacterial property and durability were characterized by measuring the diameters of inhibition rings and the minimal inhibitory concentrations (MIC). Whiteness and antibacterial property of the paint filling it were also tested. The results show that the agent has excellent antibacterial property and durability. The diameters of inhibition rings are larger than 10 mm even after 7 days. MIC is 312 g/mL and it is still low enough after durability test. The paint adding only 0.5% of it also has good antibacterial property while declining the whiteness slightly.