The invention discloses a formula of nano silicon carbide powder coating and a preparation method thereof, which comprises a component A, a component B and a component C, wherein the component A comprises an acrylic emulsion, a nanometer silicon carbide powder, a styrene-butadiene rubber and a modified high chlorinated polyethylene resin; component B comprises: feldspar powder, carborundum, ceramic micropowder, mica powder, high temperature resistant pigment, calcium carbonate, talcum powder, barium sulfate, asphalt and white cement; the composition C comprises a dispersing agent, a defoamingagent, a wetting agent, a sterilization mildewproof agent, a leveling agent, a cross-linking agent, a wetting agent, a slip-adding assistant, a film-forming auxiliary agent, a thickening agent and water; the coating has the characteristics of excellent pollution resistance, salt spray resistance, ageing resistance and wear resistance, in which, scratch resistance, adhesion and thermal shock resistance are good, the coating has excellent impact resistance, flexibility, not-easy-to crack and stable chemical stability, is not easy to be corroded by strong acid, strong alkali, strong chlorinatingagent, etc., with high service life, capable of anti-virus and anti-mildew with good combustion performance.