Abstract: The control and communication co-design for networked control systems with medium access constraints isdiscussed. A networked control system is modeled as a switched system whose input matrixes vary with medium accessconstraints. Based on the analytical methods of switched systems and optimal control theory, a dynamic scheduling optimalcontroller and the corresponding real-time switch rules are proposed. The stability of the closed-loop networked controlsystem under dynamic scheduling is also analyzed. A simulation is given to illustrate the effectiveness of the proposedmethod.