The invention relates to a vinyl acetate-acrylate copolymer emulsion, which is prepared by adopting OP-10, SDBS, SVS, water, acrylic acid and a seed emulsion as the bottom water system, taking VAc, BA and AA as the monomer, employing ammonium persulfate as the oxidant, and using sodium bisulfite as the reducing agent. Specifically, the seed emulsion in the bottom water system is prepared by using SDBS, OP-10, AA, sodium carbonate and water as the base solution, adopting VAc, BA and AA as the monomer, employing SDBS, OP-10, sodium carbonate and water as the pre-emulsification system, taking ammonium persulfate as the oxidant, and adopting sodium bisulfite as the reducing agent. The emulsion provided in the invention has a solid content of 40%-45%, viscosity (in terms of a 4-cup application amount) of 20S-26S, bonding peel strength (N / 2.5cm) of 1.4-2.5, a surface tension force of 32-37 dyne, and a film contact angle of 25-29 degrees, thus being particularly suitable for application in dry paper-plastic or plastic-plastic composite adhesives. The preparation method of the vinyl acetate-acrylate copolymer emulsion has the characteristics of mild reaction conditions and safety reaction system, thus being conducive to factory mass production.