The invention discloses a UV (ultraviolet) building coating and a preparation method thereof. The coating comprises, in percentage by weight, 10%-25% of aliphatic polyurethane acrylate, 10%-20% of epoxy acrylic resin, 10%-20% of 2-phenoxy ethyl acrylate, 10%-15% of 1,6-hexanediol acrylate, 3%-5% of 2-hydroxy-2-methyl-1-phenyl-1-one, 2%-5% of 1-hydroxy-cyclohexyl-phenyl ketone, 5%-10% of talcum powder, 10%-20% of a solvent and 2%-5% of an aid. The UV building coating prepared with the formula has excellent adhesive force, high curing rate, wear resistance, water resistance, alkali resistance, scrub resistance and weather resistance and meets performance of building coatings.