Abstract: The effect of the elastic modulus of connected piece on the mechanical properties and dynamic response of bolted joint structure was analyzed by means of theoretical analysis, numerical simulation and experimental study. Optical microscopy and scanning electron microscopy were used to analyze thread surface damage, and the effect of the elastic modulus of connected piece on the fatigue life of bolted joint structure was discussed. The results show that with the increase of the elastic modulus of the connected piece material, the relaxation coefficient Z of bolted joint structure rises, while the internal force coefficient Φ and the stress amplitude σ_α decrease. There are peeling pits, furrows and plastic flow marks on the bearing surface of bolt threads. With the increase of the elastic modulus of connected piece, the damage degree of thread surface lowers, and the residual axial force of bolt increases, leading to a longer service life.