Diffuse reflection coating with high reflectivity, preparation method thereof and reflective device

The invention discloses a diffuse reflection coating with high reflectivity, a preparation method thereof and a reflective device. The high-reflectivity diffuse reflection coating comprises aqueous resin, reflective powder and a solvent, wherein the reflective powder comprises, in percent by mass, 30-70% of titanium dioxide composite particles, 30-70% of barium sulfate and 0-3% of filler, and the titanium dioxide composite particles include titanium dioxide particles and a silica layer coated on the surface of the titanium dioxide particles. Under the irradiation action of ultraviolet ray on titanium dioxide, oxygen ions lose electrons, and are converted into atomic oxygen, and high activity is achieved at the same time; meanwhile, a photocatalysis shielding effect is achieved by the silica coated on the titanium dioxide particles, and diffuse reflection of the incident light can be improved effectively by the composite particles due to the large difference of refractive indexes between the silica and titaniu