This paper deals with the tracking problem of a space manipulator in the presence of actuator saturation. A tracking error system is first derived in the form of fully actuated system (FAS) model. Based on the FAS approach, a tracking controller is designed for the space manipulator, which makes the closed-loop system a constant linear one with an arbitrarily assigned eigenstructure. Then, in the framework of parametric method, the control gain matrices are determined by employing the optimal parameter tuning method with satisfying the input saturation constraint. Finally, a numerical simulation is performed to illustrate the effectiveness of the proposed controller.