This paper proposes UAV rendezvous and standoff tracking guidance laws against a moving target using differential geometry. Searching and subsequent tracking of moving ground based target is one of the primary capabilities of cooperative UAVs. In performing such missions, UAVs are to approach a target and keep a certain distance, known as a standoff distance. This allows target tracking without being noticed and acquisition of accurate target information. In this study, standoff target tracking is proposed using the solution of differential geometry between the UAV and the target. The proposed algorithm brings several advantages along with its inherent simplicity: rigorous stability, explicit use of a target velocity, and tuning parameter reduction. The feasibility and performance of the proposed approach is not only mathematically analysed, but also verified through realistic scenarios