This paper investigates the observer-based resilient sliding mode control problem for cyber-physical systems (CPSs). In multiple transmission channels under aperiodic denial-of-service (DoS) attacks, a decentralized dynamic event-triggering scheme is designed to reduce the network transmission burden. To construct such a periodically sampled event-triggering scheme, a set of finite-time observers is designed to obtain estimated system states. On the controller side, to obtain higher control reliability under DoS attacks, decentralized observers are correspondingly arranged in these channels. In this process, an exponential stability condition is obtained using a piecewise Lyapunov–Krasovskii functional approach. The stability conditions of linear matrix inequalities (LMIs) are given, and the computational complexity is much less compared with the counterparts in some existing results for multiple channels. To further improve the disturbance rejection performance, a weighed integral-type sliding surface is introduced, and the impact of unreliable state estimating channels is reduced. An auxiliary system is also designed to handle the input saturation, and the closed-loop system under DoS attacks is asymptotically stable. Finally, an example of an unmanned aerial vehicle is given to verify the effectiveness of the obtained resilient control approach.