The invention discloses a remoldable shape memory bismaleimide resin and its application. The preparation method includes blending 2-allylphenyl glycidyl ether and adipic acid in acetonitrile, carrying out an esterification reaction under the condition of quaternary ammonium salt as a catalyst to obtain bis(3-(2-allylphenoxy)-2-hydroxypropyl)adipate containing a reversible dynamic group; then uniformly mixing bis(3-(2-allylphenoxy)-2-hydroxypropyl)adipate and bismaleimide, curing to obtain the remoldable shape memory bismaleimide resin. The prepared remoldable shape memory bismaleimide resin is not only excellent heat resistance and mechanical properties, but also can be remolded under hot pressing conditions. The preparation method of the remoldable shape memory bismaleimide resin has the advantages of wide raw material sources and simple process, and has a wide application prospect in the fields of aerospace, transportation, electronic information, new energy, insulated electrical industry and the like.