The invention discloses a self-cleaning nanometer composite environmental protection latex paint and preparing method, which comprises the following parts: 0.5-5% wetting disperser, 0.5-50% nanometer concentrated slurry, 0.5-10% hydrophobic agent, 0.5-10% anion powder, 0.5-8% filming adjuvant, 0.1-2% anti-settling agent, 0.8-10% antifreeze agent, 0.1-3% defoamer, 4-30% dye, 0-30% filler, 15-45% emulsion, 0.1-4% thickener, 0.1-3% levelling agent, 0-3% pH adjuster, 0-4% microbe eliminating agent and 0.5-45% water. The preparing method comprises the following steps: 1) placing water in the container with high-speed disperser; adding microbe eliminating agent, nanometer condensing slurry, hydrophobic agent, anion powder; blending evenly; adding dye and filler; dispersing until finesse reaches 20-60um; 2) adding emulsion, pH value adjuster, thickener and leveling agent continuously.