In order to accurately predict the exoteric aerodynamic heat and internal temperature of a hypersonic projectile and the charge temperature distribution, a numerical simulation of coupled heat transfer of hyper sonic flow field and structure temperature field was carried out when a layer of thermal protection material was added. The heat transfer between different phases was realized by fluid-solid coupling interface. Projectile surface temperature and the temperature variation of internal projectile and charge at each moment were calculated. The results showed that the fluid-solid coupling method was adopted to simulate the aerodynamic heat for more reasonable and practical projectile temperature data.