The invention relates to a water-based 
metal ink for UV offset ink and a preparation method thereof. The water-based 
metal ink comprises the following components by weight: 25-35 parts of 
water soluble resin, 30-50 parts of a 
solvent, 1-5 parts of a 
photoinitiator, 10-30 parts of a metallic 
pigment, 2-5 parts of a fastness assistant, 2-4 parts of a leveling assistant and 1-3 parts of a 
wetting and dispersing assistant. Specifically, the 
solvent is a mixed 
solvent of deionized water and 
ethanol in a 
mass ratio of 1:1, the metallic 
pigment is 
bronze powder or aluminum silver 
powder. The preparation method includes: firstly fully mixing the metallic 
pigment with the solvent evenly, then adding 
water soluble resin, the 
photoinitiator and assistants in order, stirring the materials fully till uniform dispersion, then carrying out filling, sealing and packaging, and performing 
aluminum foil sealing, thus obtaining the water-based 
metal ink finished product. Compared with the prior art, the water-based metal ink provided by the invention is green and environment-friendly, has the advantages of good binding fastness with UV offset ink, difficult fall, simple preparation process, good finished product stability, and production cost saving, and is suitable for 
industrial scale and high efficiency production.