In this paper,solar-sail attitude control system which employed moving masses for pitch/yaw trim control and roll stabilizer bars for roll control was studied.Physical model of solar-sail attitude control system had been analyzed,and the dynamical model was established using Euler’s attitude dynamical equations.According to the model,a nonlinear PID controller was found to control the three-axis attitudes.Finally,a series of simulations,including the Solar Polar Orbit Radio Telescope misson’s trajectory transfer,were run to determine the effectiveness of the attitude controller and characterize the behavior of attitude control method using moving masses and RSB.