In this paper, we show the design method of the networked control system with structured uncertainty. In this system, the plant and the controller are connected with a communication bus. The plant and controller are denoted as LTI-system, but the communication bus has a periodic characteristic. So that the whole of the system characteristics is denoted as a periodic system. In this paper, we consider the guaranteed cost control in the case with the linear time-varying system. As this result, we derive the stochastic discrete algebraic Riccati equation of the time-varying case and apply this equation to the design problem of networked control system. In the numerical example, the plant is car-pendulum system with uncertainty. Through the numerical result, we show the effectiveness of our proposed method.