Abstract: Lightning strike protection is crucial for flight safety. Wings are more frequently struck by lightning, but there is a lack of research on the damage of materials during the conduction of lightning current inside. In this paper, the damage characteristics of three kinds of carbon fiber composite assemblies with fasteners wrapped with adiabatic film, conductive film and no treatment under lightning impulse conduction were investigated by experimental and simulation methods. The thermal-electrical coupling model was established by using Abaqus finite element simulation software, and the temperature, electric field and current distributions were obtained under the condition of lightning current lateral injection. Simulation and experimental results show that there is a small air gap between the fastener and the hole wall, which is easy to breakdown when the lightning current flows through, generating high temperatures and sparks, and causing damage to the assembly; both gap treatments reduce the damage to the assembly during the lightning current conduction process, but the film will be degraded to varying degrees; if the fastener is wound with conductive film, the delamination decreases, the current flows through the fasteners in the direction of the layup, and the high temperature zone is formed at the intersection of the fibers and the fasteners. The delamination is exacerbated by the wrapping of the insulating film, where the current bypasses the fastener and collects at the fiber tangent to its edge, creating a high-temperature zone. This experimental and simulation study can bring new ideas for lightning protection of composite materials with fasteners.