Erosion wear and fatigue cracks are the key factors causing the failure of gun barrel.Erosion wear leads to a decrease in shooting accuracy，while the propagation of fatigue cracks can weaken the barrel strength and potentially lead to catastrophic explosion，posing a potential threat to the safety of gun launches.For this purpose，a construction scheme for a digital twin model of gun barrel based on fatigue fracture simulation is proposed.This involves developing the high-fidelity geometric and finite element models of gun barrel and comprehensively considering the effects of the high-temperature，high-pressure impact loads and their coupled interactions，as well as the structural and manufacturing factors such as coatings and preload forces.A digital twin simulation model for gun barrel is constructed based on elucidating the propagation behavior of micro-cracks on the inner wall of gun barrel.Building upon the health monitoring and remaining service life evaluation method for gun barrels based on outer wall strain measurements，the real-time online detection of damage parameters for crack propagation in gun barrels is achieved.This scheme lays the foundation for constructing an interactive digital twin model of gun barrels and provides a new technical path for preventing the barrel burst and achieving the dynamic prediction of barrel life.Finally，the key technologies for constructing the digital twin model of gun barrels atr proposed，which can serve as a valuable reference for digital twin research on other barrel-type weapon systems.