The traditional spacecraft control system is based on its own attitude and orbit position, combined with the orbit of the relay satellites, and outputs control instruction to the relay terminal to achieve open-loop pointing control of the relay antenna to the relay satellites. However, due to the constraints such as orbit calculation accuracy and attitude control accuracy, the pointing control accuracy is poor. In this paper, a high precision composite control method of relay antenna based on Radio-frequency (RF) signals is proposed. First, the theoretical pointing calculation result of relay antenna is given according to the attitude and orbit informations. On the basis, the RF error signals are introduced for closed-loop correction, which can effectively reduce the impact on attitude control and orbit calculation accuracy, so as to achieve high-precision pointing control of the relay antenna. Mathematical simulations show that the proposed approach can improve the pointing accuracy of relay antenna from 0.2° to 0.01°