The invention relates to an organic silicon-modified water-based UV (ultraviolet) coating and a preparation method thereof, and belongs to the technical field of environment-friendly coatings. The organic silicon-modified water-based UV coating comprises the following components in percentage by mass: 30 to 55 percent of organic silicon-modified hyperbranched water-based urethane acrylate, 20 to 50 percent of filler, 1 to 10 percent of photoinitiator, 0 to 3 percent of auxiliaries and 5 to 30 percent of water. The preparation method comprises the following steps: fully grinding the organic silicon-modified hyperbranched water-based urethane acrylate, the filler and water in a proportion, performing dispersion for 1 to 2 hours at 40 to 50 DEG C at a rotating speed of 400 to 600rpm, adding the photoinitiator and the auxiliaries, and uniformly stirring and standing a mixture to obtain the water-based UV coating. The coating is environment-friendly, nontoxic, high in curing speed, stability, aging resistance, solvent resistance, adhesive power and abrasion resistance and suitable for a plurality of coating modes and production requirements, and can be widely applied to the surfaces of automobiles, electronic products, ships, furniture and packaging printing materials.