Abstract: Based on the coupling theory,numerical simulations are carried out for the influence of different parameters on frequency response of a coaxial Bragg structure with low frequency (15GHz)single-mode and high frequency(0.35THz)coupling modes.Results show that the initial phase,the ripple period,windowing-function technique,the sinusoidal ripple amplitude,the ripple shape,the mode of gradient and the gradient,and the length of a coaxial Bragg structure all evidently influence the frequency response of a coaxial Bragg structure.The inner and outer conductors of corrugated coaxial Bragg structure phase difference is set to 180°,the ripple period is the same,the window technique can well inhibit the residual side-lobes,and when we change the sinusoidal ripple amplitude,the ripple shape,the mode of gradient and the length of the structure can change the bandwidth and reflectivity of coaxial Bragg structure,especially for the high frequency coupling modes,the influence of different parameters on the working mode and competition mode is different.Therefore,different parameters can be properly chosen to improve the mode selectivity of coaxial Bragg structures and to improve the performance of coaxial Bragg structure.