The work aims to use waste PET degradation products after pretreatment as chain extender to prepare adhesives with no formaldehyde release, strong adhesion, good durability and certain mechanical properties to replace traditional formaldehyde-based adhesives. A new type of polyurethane adhesive (PUa) was synthesized by elution of oligomer polyol prepared by high efficiency degradation of waste PET, and then step polymerization reaction with isocyanate. At low temperature/room temperature, PUa had bonding properties, and the adhesion strength to paper, glass, wood and other substrates exceeded 126 kPa. After 38 cycles of adhesion-deadhesion-adhesion, it still retained at least 39.2% adhesion, and had excellent repeatable bonding properties. The new polyurethane adhesive made from waste PET has good thermal stability and bonding properties, good environmental adaptability, and has great potential application value in the field of lightweight buffer packaging. The research can provide high value-added solutions for the resource utilization of plastic waste, and can also provide new ideas for alleviating the shortage of oil resources and the sustainable development of the adhesive industry.