This paper investigates the robust distributed model predictive control (DMPC) based consensus problem of general linear discrete-time multi-agent systems subject to external disturbances. We first propose a robust DMPC based consensus algorithm, mainly relying on the DMPC based consensus of a nominal system whose state deviation from the actual state is bounded by an invariant set. We then prove the feasibility and robust consensus of the proposed algorithm. Finally, we present a numerical example to verify the theoretical results.