This paper investigates the consensus problem of a general linear multi-agent systems(MAS) with variable time delays. Firstly, a protocol based on the combination of the state feedback and the distributed PID control law is proposed. Then, the state space of the system is decomposed into a consensus subspace and a consensus complement subspace, on this basis, the sufficient and necessary condition of the consensus of the MAS is given by using the state space decomposition approach. The explicit form of the consensus functioin is given. Finally, a new Lyapunov-Krasovskii functional is constructed, and the parameters of the control system are given based on the linear matrix inequations(LMIs). An extented method is introduced to decrease the computation of the LMIs. The simulation results show that, under the condition that the topology has a global reachable node, through calculating proper PID parameters and control parameters, the proposed protocol can overcome the delay to some extent, so that the MAS can achieve consensus and have strong robustness. Through comparing with the pure propotional control, the proposed protocol can eliminate the steady-state error finally and make the system achieve consensus.