Motivated by the potentially application merits of wireless networked control systems (WNCSs), this paper presents a network-based formation framework for multi-agent systems. First, we construct a discrete formation protocol by integrating 802.11b. Meanwhile, one agent is considered as the reference, and the other ones keep a desired formation with the reference via communication networks. Using Lyapunov stability theory, sufficient convergence conditions are derived, and the verification problem of the sufficient conditions can be transformed as a linear matrix inequality (LMI) feasibility problem. Solving this LMI feasibility problem, a networked-based feedback controller can be easily obtained. Finally, simulation studies are provided to demonstrate the effectiveness of the proposed method.