Dear Editor, This letter investigates the target enclosing control problem of multi-agent systems. A signed graph-based control strategy is presented, where the agents are steered to enclose the dynamic target from both sides as they move. This is inspired by the phenomenon that signed networks exhibit bipartite clustering if the underlying graph is structurally balanced, so that the agents may naturally enclose the zero point from opposite sides (+ and -) if proper controllers are applied. By adopting a distributed observer to estimate the information of dynamic target, a consensus-based enclosing control scheme is designed. Furthermore, a complete Laplacian matrix (CLM)-based Lyapunov analysis method is introduced to prove the control stability, which provides simpler theoretical validation for the stability analysis of average consensus than the conventional method based on state transition matrix. Finally, some numerical simulations are shown to verify the effectiveness of the proposed control scheme.