In this paper, the Lorentz finite-difference time-domain method (Lorentz-FDTD) is used to study the interaction between high-speed moving cone-sphere target coated with plasma sheath and electromagnetic (EM) wave. When the target is in different moving states, the influence of moving state on radar echo and radar cross section (RCS) of target coated by plasma is analyzed in this paper. Firstly, the Lorentz-FDTD algorithm in dispersion media is derived. And then, the electromagnetic scattering characteristics of the moving cone-sphere target coated by plasma is studied with the Lorentz-FDTD method. The calculation results show that the motion state of the target will modulate the frequency and amplitude of the scattered EM waves. Besides, the plasma sheath coated on the surface of target will have an effect on the target far-scattered field.