An event-based security control for networked control systems(NCSs) under two-channel denial of service(DoS) attacks is presented in this paper.First,a model is proposed to describe the DoS attacks with a compensation strategy and applied to the sensor-controller channel and controller-actuator channel of the NCSs.Second,an event-triggered mechanism is proposed to induce the burden of information transmission.By definition,information can transfer only when the trigger condition is met.According to the optimal control theory and linear matrix inequality,sufficient conditions of the closed-loop system with a certain probability of the input-to-state security are derived,and the controller is designed.Finally,the effectiveness of the controller is verified through computer simulation.