As a system to collect clean energy from outer space, the solar power satellite (SPS) has attracted great concerns of various countries and scientific research institutions in the world. As SPS is a very large flexible and lightweight structure in outer space, it is necessary to investigate the coupling effect of orbital motion, attitude motion and structural vibration in the study of the global dynamics. In this paper, under the consideration of the effects of the nongravitational perturbation forces, the coupled orbital, attitude and structural Hamiltonian equations of the integrated symmetrical concentrator (ISC) are constructed by using Legendre transformation and introducing generalized momenta. Subsequently, the dynamic equations of the system are solved by the symplectic RungeKutta method. According to the numerical results, the effects of nongravitational perturbation of Order 2 are well discussed, and the variation of total energy is analyzed.