The invention discloses environment-friendly latex paint used for an interior wall. The environment-friendly latex paint is prepared from the following raw materials: epoxy resin, acrylic resin, castor oil, dimethyl silicone oil, sodium alginate, polyoxyethylene aliphatic ether sodium sulfate, mica powder, carboxymethylated chitosan, zinc sulfate, 4-methyl-4'-vinyl benzophenone, 2,2,6,6-tetra-methylpiperidine benzoate, a curing agent, ethanol and water. A preparation method comprises the following steps: preparing resin mixed liquor, mixing in the castor oil, dimethyl silicone oil, 4-methyl-4'-vinyl benzophenone and 2,2,6,6-tetra-methylpiperidine benzoate, preparing an aqueous solution, mixing in the aqueous solution, and dispersing the mica powder and the curing agent. The latex paint disclosed by the invention has the advantages that raw materials are cheap and available, environmental friendliness, scrubbing property, good antibacterial effect, appropriate workability, good stability, difficulty in ageing and direct brushing are realized, and the preparation method provided by the invention is low in requirement on equipment and reasonable and simple in operation, so that industrial production can be carried out.