The high flexibility and low damping of large deployable antenna has been proposed as critical requirement not only for the stability control of the antenna itself, but also for the attitude control of the satellite. Under the development of a large flexible deployed antenna, a frequency optimization design and disturbance response analyses are conducted for the antenna. Moreover, an improvement of the designis achieved by the sensitivity analysis of the modal frequency to the stiffness of the support structure and the stiffness of the scanning mechanism. Modal analysis and test are carried out, and the influence of pitch angle and azimuth angle to the moment of inertia and modal frequencies are given for -10°~25° and -10°~10° combination modes. Further simulation investigates the root mean square and the pointing error response of the antenna reflector under a given satellite disturbance, and the simulation results revealed that the large deployable antenna is insensitive to the disturbance after the frequency optimization.