Abstract: Based on the quadratic stability theory, the robust H_∞ control problem for uncertain discrete-time systems with timedelay was deal with. The problem of robust H_∞ control with memory state feedback was discussed by linear matrix inequality approach. The sufficient condition for a robust H_∞ controller was derived. An H_∞ state feedback controller was designed and the controller could be solved by one LMI. An illustrative example was presented to prove the correctness of this method.