This paper studies the dynamic characteristics of an electric solar wind propulsion system. To study the coupled interaction of the orbital and self-spinning motions of an electric solar wind propulsion system, a high-fidelity model is built up by using the nodal position finite element method, where the axial elastic and transverse dynamic motions of tether with the electric effects are considered. The coupling effects between the orbital and self-spinning motions are identified and explained, its results show that they have a significant impact on the system dynamics.