The invention relates to practical printing ink, in particular to six-color full-color soft printing ink and a preparation method thereof. The six-color full-color soft printing ink is mainly prepared from 11.5 to 31.5 parts of dye, 57 to 77 parts of binder and 6 to 27 parts of accessory ingredient, wherein the dye contains an organic pigment, a inorganic pigment or a mixture of the organic pigment and the inorganic pigment; the binder mainly contains: water-soluble acrylic resin, polyether-modified acrylic acid polyurethane resin, cellulose acetate butyrate, rosin modified phenolic resin, polyvingakohol, glycerin, ethyl acetate, sodium diacetate, decabromodiphenyl ether, n-butyl acetate, polybasic acrylic copolymer resin and polyketone resin; the accessory ingredient is one or more of a color adjustment agent, a plasticizer, a thickener, an organic diluting solvent, a liquidity adjustment agent, a gel, an adhesion removal agent, a surface active agent or talcum powder. According to the six-color full-color soft printing ink and the preparation method thereof provided by the invention, the performances of the binder and the accessory ingredient are improved, so that the printing ink with a favorable performance is obtained, and an excellent printing effect is obtained when in use.