The rate-dependent hysteresis exhibited by magnetostrictive actuator (MA) presents a challenge in modeling of these actuators. In this paper, a novel rate-dependent hysteresis model was proposed for magnetostrictive actuator. In the model, the modified Prandtl-Ishlinskii operator (PI) is combined with a second order ordinary differential equation in a cascaded structure. The modified PI operator is used to account for the static hysteresis, the connection between ODE and the rate-dependent energy loss was established, including the classical eddy current loss and the mechanical dynamics. Simulation results show a good agreement with the experiment ones.