The invention discloses ultraviolet-curing marking ink and a preparation method thereof. The ink mainly consists of the following components in parts by weight: 40-59 parts of photosensitive resin, 4-8 parts of tripropylene glycol diacrylate and / or derivatives thereof, 2-5 parts of isobornyl methacrylate and / or derivatives thereof, 2-6 parts of photosensitizer, 10-25 parts of filler, 0-5 parts of mill base, 0.5-3 parts of auxiliaries, and the like. After being grinded, the ink has lower viscosity, is suitable for being printed on a single sided board of a circuit plant to achieve effect of marking names of electrical appliance elements. And meanwhile, the printed characters have very good third dimension, high heat resistance, high adhesion and insulation after being ultraviolet-cured.