The invention discloses a concealed theft-proof latex paint and a preparation method thereof. The latex paint consists of deionized water, cellulose, dispersant, wetting agent, defoaming agent, black silicon wafer powder, pigment and filler, preservative, defoaming agent, polyacrylic emulsion, pH adjusting agent and thickening agent. The latex paint has the advantages of clear thermally-formed image, high sensitivity, good vibration resistance and the like, is not affected by environments (such as electromagnetic radiation, nuclear radiation, illumination and the like), and can keep better performance under the climatic conditions of fog, rain, snow and the like; the thermally-formed image has good concealed protection; the latex paint can be displayed without image in a visible light range, complements the prior theft-proof art, is directly brushed or sprayed on the wall as common latex paint, and can be used for key theft-proof sections of curve boundary; and the latex paint has the advantages of convenient construction, low cost and long theft-proof property, does not need any maintenance cost, and does not need any power supply equipment.