Abstract: Since the wireless network time-varying delay and communication channel bandwidth have great effects on networked control systems(NCSs), this paper studies an event-triggered scheme and a $H_{\infty}$control co-design method. Initially, a delay mathematic model of NCSs is constructed. In consideration of wireless network time-varying delay between event generator and zero order holder, this paper designs an improved event-triggered communication scheme. Furthermore, by applying a new Lyapunov-Krasovskii functional and linear matrix inequality method, a criterion for the delay-independent $H_{\infty}$ stabilization is derived, and the co-design method for gaining the trigger parameters and state feedback $H_{\infty}$ control is proposed. Finally, an inverted pendulum example is provided to illustrate the effectiveness of the proposed event-triggered scheme and the co-design method.