The invention discloses a water-based polyacrylic emulsion laminating adhesive and a preparation method thereof, which belong to the field of adhesives. The laminating adhesive with solid content of between 40 percent and 50 percent is prepared from raw materials of monomers, an emulsifier, an initiator, a buffering agent, a pH regulator, a waterborne aid and deionized water by adopting steps of pre-emulsification, seed reaction, polymerization and compounding, wherein the monomers include a hard monomer, a soft monomer and a functional monomer containing -COOH and -OH groups; the emulsifier consists of alkyl ether ammonium sulfate, sulpho sodium succinate and allyloxyl alkyl sodium sulfonate in the ratio of 2:1:(0.4-0.8); and the waterborne aid comprises a waterborne wetting agent, a waterborne defoaming agent and a waterborne preservative. The allyloxyl alkyl sodium sulfonate serving as a reactive emulsifier is introduced into the laminating adhesive, so that the influence of the migration of emulsifier micromolecules onto a paper / plastic interface is reduced, and initial adhesion and bonding strength are enhanced; and the functional monomer containing the -COOH and -OH groups is introduced, so that the bonding strength is enhanced, and the low-temperature adhesive property and ink affinity are improved.