This paper takes networked control systems(NCSs) with networkinduced delay as the research object, combined with the eventtriggered mechanism, which studies the stability of NCSs under denial of service(DoS) attacks. In the process of DoS attacks, the sensor of NCSs cannot receive the measurement information in time, or the actuator cannot get the control information, then there will be unstable subsystems. In order to improve the stability of NCSs, firstly, NCSs is modeled as a closedloop switched system with both stable subsystems and unstable subsystems. The model can handle of networkinduced delay and DoS attacks uniformly. Then, based on the analysis method of the switched system, a sufficient condition is derived from the concerned NCSs to be exponentially stable. Furthermore, the time ratio of the DoS attack is also analyzed, the concerned NCSs is always guaranteed to be exponentially stable, as long as the occurring probability of DoS attacks is in the effective range. Finally, the experimental results show that NCSs can obtain the corresponding exponential stability for 0<δ<3; the stability of NCSs with eventtriggered mechanism under the DoS attack is given to show the effectiveness of the proposed result.