A microwave-strengthened supramolecular adhesive by introducing maleic acid amide bonds into the cross-linked networks of catechol-based monomers and iron oxide nanoparticles is reported. Under microwave irradiation, the supramolecular adhesive can be rapidly heated up, causing the transformation from maleic acid amide bonds to maleimide bonds and thus the increase of its cohesive strength. The supramolecular adhesive can flexibly bond substrates like pressure sensitive adhesives during the bonding procedure and shows an adhesion strength of 0.5 MPa toward ceramic. After microwave strengthening, it can strongly bond substrates like hot melt adhesives and shows a dramatically increased adhesion strength of 5.0 MPa, 10 times stronger than the original value. Moreover, the microwave-strengthened supramolecular adhesive can be reused 3 times with negligible loss in adhesion strength, exhibiting outstanding multiple reusability. By combining both high flexibility and high adhesion strength, it is anticipated that the supramolecular adhesive can be of great potential in cultural relics restoration and microelectronics.