In this brief, an observer-based dynamic event-triggered control for cyber-physical systems (CPSs) with multiple cyber-attacks in dual channels is investigated. Firstly, An observer model is introduced to address the issue of state unmeasurability of the system. Secondly, to mitigate the impact of limited network-resources, a dynamic event-triggered protocol is adopted. Thirdly, considering the effect of cyber-attacks in the presence of dual channels, an observer-based feedback control method is proposed. The stability and <inline-formula> <tex-math notation="LaTeX">{H}_ {\infty }/H_{2} </tex-math></inline-formula> performance of CPSs are established by utilizing a new Lyapunov function and LMI method. Finally, an example is simulated to demonstrate effectiveness of the method in this brief.