Firstly, this paper proposes a novel protocol based on distributed PID control law and introduces a descriptor method to transform the differential equations of the closed systems into a descriptor model, transforming the consensus problem into an asymptotic stability problem. And then a Lyapunov-Krasovskii functional is constructed and the parameters of the consensus protocol are given based on the linear matrix inequality(LMI). The simulations show that if the topology contains a globally reachable node, through selecting appropriate PID parameters, the MAS can achieve consensus, and the uncertain parameters will cause bad effect to the trajectories of the systems. Compared with the PD-Control-Based consensus protocol, the proposed protocol makes the swarm systems converge faster, and the robustness stronger.