The invention discloses ultraviolet-cured ink for a composite board. The ultraviolet-cured ink is prepared from the following components in percentage by mass: 10 percent to 20 percent of a monomer, 35 percent to 45 percent of light-sensitive resin, 6 percent to 8 percent of a photoinitiator and 30 percent to 36 percent of powder, wherein the monomer is a mixture of alpha-(1-oxo-2-allyl)-omega-phenoxy-polyethylene oxide and di-trimethylolpropane tetraacrylate; the photoinitiator is a mixture of benzoin dimethyl ether and 2,4,6-trimethyl benzoyl ethyl phosphate. The ink for the composite board, disclosed by the invention, has the advantages of economical efficiency, energy saving, rapid curing speed, environment friendliness, commonality and the like. Meanwhile, the invention further discloses a preparation method of the ultraviolet-cured ink for the composite board.