There is a complex dynamic coupling process between lightning arc and carbon fiber reinforced polymer materials with the fastener during lightning attachment. This study investigates the evolution characteristics of the lightning arc and the interaction mechanisms of the action of the arc on CFRP materials with fastener through the MHD model for lightning current component B. The results demonstrate that the high-temperature region is located at the center of the arc channel, while the pressure difference and high gas velocity promote the outward expansion of the arc channel on the surface of the specimen. The fastener significantly reduces the maximum surface temperature and increases the maximum pressure. Material property differences between the fastener and CFRP materials result in higher magnitude current and heat flux densities on the surface of the fastener, while also reducing the impact of the lightning arc on the CFRP materials.