Abstract: Conformal load-bearing antenna has good comprehensive properties. It not only can be used for electromagnetic radiation, but also can bear load. Therefore, it is of great value in aviation field and has good potential for future development. Conformal load-bearing antenna is composed of layered structures. Bonding defects such as cracks may arise in bonding layer when layers with different materials are bonded and hot-pressed, and structural failure usually appears in those cracks. Therefore, it is of great significance to study the mechanical properties evolution mechanism of conformal load-bearing antenna with bonding defects. Firstly, based on experimental data, the dynamic equivalent fracture energy of the antenna layer interface is identified and applied to the bilinear cohesion zone model. Secondly, the finite element model of the antenna is established and the accuracy of the model is verified according to the experimental results. Finally, the maximum crack size permitted in the structure service cycle is obtained according to the simulation results, and it provides the basis for the reasonable determination of manufacturing accuracy in engineering.