The invention discloses an odorless anti-formaldehyde environment-friendly internal wall latex paint and a preparation method thereof. The odorless anti-formaldehyde environment-friendly internal wall latex paint is prepared from the following components in percentage by weight: 1-15% of visible light induced nano titanium dioxide photocatalyst slurry, 15-35% of odorless emulsion, 1-15% of formaldehyde absorbent, 0.5-2% of dispersing agent, 0.2-3% of thickening agent, 0.2-1% of wetting agent, 0.1-1% of defoaming agent, 0.5-5% of film-forming assistant, 0.2-3% of anti-freeze agent, 20-40% of pigment and filler, 0.1-1% of pH regulator, 0.01-0.1% of anticorrosive bactericide and 15-40% of deionized water. The invention adopts an IPS+odorless technique, and the visible light induced nano titanium dioxide photocatalyst and the formaldehyde absorbent are added, thereby achieving the optimal effect of removing formaldehyde and other harmful substances through physical adsorption and chemical decomposition. The invention can be widely used for decorative spraying of various internal walls and other constructions.