The invention discloses a waterborne plastic-absorbing glue and a preparing method thereof. The waterborne plastic-absorbing glue is prepared from, by weight, 40-60 parts of aromatic aqueous polyurethane dispersion, 40-60 parts of ethylene-vinyl acetate emulsion, 0-10 parts of tackifying resin, 0.05-0.5 part of antifoaming agent, 0.1-1 part of wetting agent, and 0.1-1 part of thickening agent. The plastic-absorbing glue has excellent heat-resistant performance, pickup rate, bordure performance, low-temperature viscosity stability, and low activation temperature. The preparing method comprises the steps of adding aqueous polyurethane dispersion and ethylene-vinyl acetate emulsion into a high-speed dispersing kettle, then adding the tackifying resin, wetting agent, and antifoaming agent in sequence under a stirring condition, and finally adding the thickening agent to adjust the mixture into suitable viscosity to obtain the waterborne vacuum plastic-absorbing glue. According to the waterborne plastic-absorbing glue and the preparing method thereof, it is not necessary to adjust the pH of the ethylene-vinyl acetate emulsion in advance, and thus preparation procedures of traditional plastic-absorbing glue are simplified, and deslagging risks in the preparing process are lowered.