The invention discloses a high-solid low-viscosity laser alumite imaging layer coating and a preparation method thereof. The high-solid low-viscosity laser alumite imaging layer coating is prepared from the following raw materials in parts by weight: 10-30 parts of polymethyl methacrylate resin, 5-10 parts of styrene-maleic anhydride resin, 1-5 parts of cellulose acetate butyrate, 5-10 parts of isobornyl methacrylate, 1-5 parts of fluorine-containing polyacrylate, 50-70 parts of butanone, 1-8 parts of n-propyl acetate and 1-5 parts of propylene glycol ether. Polymer monomers contained in the formula of the imaging layer coating are of special structures or functional groups, and meanwhile comprehensive performance of polymer is taken into consideration; under the condition that the performance, such as heat resistance, of the polymer coating is not influenced, the viscosity of polymer solution can be obviously reduced, the using amount of an organic solvent is reduced, the leveling property of a coating film in the coating process is improved, and the coating film also has relatively low surface energy, so that acting force between a laser operating plate and a polymer coating layer in a high-temperature mold pressing process is reduced to achieve an effect of preventing plate adhesion.