The invention relates to compound printing ink, in particular to ester-soluble polyurethane compound printing ink and a preparation method thereof. The compound printing ink comprises the following components by weight percentage: 27 to 32 percent of modified polyurethane resin, 6 to 15 percent of vinyl chloride-vinyl acetate copolymer liquid, 8 to 33 percent of a pigment, 0.4 to 0.8 percent of a dispersing agent, 0.3 to 0.5 percent of wax powder, 0.2 to 0.8 percent of an antistatic agent, 0.2 to 0.5 percent of an anti-precipitating agent, 0.5 to 1.5 percent of an adhesive force reinforcing agent, 10 to 25 percent of propyl acetate, 5 to 15 percent of ethyl acetate, and 10 to 20 percent of butyl acetate. The compound ink prepared in the invention has the advantages as follows: the tinting strength is high; the color is bright; the transparency is high; the printing adaptability is high, so that the compound printing ink can be widely applied to high-low speed printing of plastic flexible packaging composite materials such as PET, NY and BOPP; the adhesive force to various plastic film base materials is great, and firmness is achieved; resistance to corrosion of acid, alkali and the like is high; hot adhesion phenomena are avoided; the water resistance is high; the temperature resistance is high, so that the compound printing ink can meet the processing requirements of follow-up processes such as boiling, high-temperature cooking, food refrigerating, and is high in storage stability.