This brief is concerned with the robust stabilization issue of cyber-physical systems (CPSs) under periodic Denial-of-Service (DoS) attacks with quantized feedback sliding-mode control (SMC) based on event-triggered mechanism(ETM). The ETM is introduced for reducing the load of network communication, and states generated by the ETM are quantized to construct the available information of the design of sliding-mode controller. Sufficient conditions for robust stabilization of the system under periodic DoS attacks are proposed to ensure the reachability of sliding manifold. In addition, a lower bound of the quantized measurement saturation parameter is derived to guarantee the quantizer capture system states in only one step under periodic DoS attacks. After that, this brief proves that the execution time interval of the ETM has a positive lower bound and thus no Zeno behaviors occur. The effectiveness of this proposed method is finally verified by an example of a satellite control system.