Many on-board payloads for monitoring, communication and Earth imaging have extensive requirements for target tracking maneuvers in many space missions. A quaternion-bas ed PID feedback control for ground-target tracking of a three-axis stabilized Earth-pointing satellite is systematically analyzed. Based upon the orbital measurement of the satellite position and velocity by an accurate GPS receiver, we present a general method to compute the quaternion error and its integral error with respect to the commanded ground target for any selected pointing axis of the satellite. In addition, an optimal way to derive the desired angular velocity reference for tracking is discussed in detail. Three-axis reaction wheels are employed to demonstrate the feasibility of this control algorithm on a imaginary low-Eartheccentric-orbit satellite. A special tracking scheme for the pointing axis along the body z-axis of the satellite was also investigated. This scenario can be readily applied in real-time for practical target tracking with high accuracy.