The invention provides an adhesive system suitable for insensitive munitions and a preparation method. The adhesive system is prepared by, by weight, 40-50 parts of polyol, 30-60 parts of energetic plasticizer, 5-10 parts of polyisocyanate, 0.0002-0.001 part of catalyst. During preparation, raw material preprocessing including the rotary evaporation dewatering of the polyol and the energetic plasticizer and raw material preheating is performed during preparation, the polyol and the energetic plasticizer are then premixed, and a curing agent is added finally and sufficient and uniform mixing isperformed to perform curing at 55-65 DEG C for 4-7 days. Compared with a traditional hydroxyl-terminated polybutadiene-based (HTPB-based) adhesive system, the adhesive system is high in oxygen content, good in compatibility with the energetic plasticizer, and capable of evidently increasing the energy output of an explosive system; the adhesive system is mild in reaction under a heat stimulationcondition and melts and expand when being heated to break through a munition shell, explosion possibility under the heat stimulation condition is lowered, and munition insensitivity is increased.