A robust sliding mode synchronization control method under the Delta operator framework is proposed for nonlinear chaotic systems under DoS attack and network failure.Firstly, based on the Delta operator theory, a unified model for continuous and discrete time nonlinear chaotic systems under the Delta operator framework is established.Secondly, the corresponding linear sliding mode surface is designed for the Delta operator chaotic synchronization error system, and the sufficient conditions for the existence of the sliding mode surface are given by using the Linear Matrix Inequality (LMI) method.Thirdly, the sliding mode controller is designed for the synchronization error system, so that it can reach the sliding mode surface quickly in finite time and realize the asymptotic synchronization of the nonlinear chaotic system.Finally, the simulation results show that under the designed controller, the synchronization error tends to zero and the asymptotic synchronization is realized, which shows the feasibility and effectiveness of the proposed method.