This paper studies the forced vibration behavior of magnetostrictive actuator eradiation plate excited by a variable force due to displacement excitation produced by magnetostrictive bar inside the magnetostrictive actuator through a single elastic ring between concentric point of the plate and the end of the bar. Meanwhile, the influence of elastic coefficient of the ring on amplitude of plate vibration is discussed also. The calculating model and the analytic method discussed in the paper are useful to determine the structure and the dimension of eradiation plate as well as to optimize the working parameter matched in the system.