To set-up a rate-dependent dynamic hysteresis model, eddy current loss in giant magnetostrictive material is represented by the loss in eddy current impedance. By combining static Jiles-Atherton hysteresis model, the equivalent circuit of giant magnetostrictive material is built, the relationship between eddy current impedance and magnetic field and magnetization is derived and the maximum eddy current impedance of the material is clculated. Effective magnetic permeability is applied to estimate the eddy current impedance as exciting rate or frequency gets high. Simulation and experiment results of exciting frequencies at 5Hz,10Hz,20Hz, are compared, showing experiment results are coincident with simulation ones, in term of magnitude order and tilt direction. It is demonstrated that effective permeability is feasible for eddy current impedance estimation and eddy current impedance-based dynamic Jiles-Atherton hysteresis model is able to reflect practical dynamic hysteresis.