Abstract: After analyzed the photocatalytic theory of nano-TiO₂ and the antibacterial theory of Ag⁺ and Ce⁴⁺, interior latex coatings were modified by anatase nano-TiO₂ loading Ag⁺ and Ce⁴⁺ to prepare environmental protection coatings with air cleaning and antibbacterial ability.The qualitative antibacterial annulus, quantitative antibacterial rate and degradation formaldehyde of modified interior latex coating were tested.The results show that the interior latex coatings modified by anatase nano-TiO₂ loading Ag⁺ and Ce⁴⁺ have good inhibiting bacterium and degrading formaldehyde ability.The antibacterial rate exceeded 99% after 24 h and over 75% formaldehyde was degraded after 8 h irradiation with 40 W daylight lamp.