In the mordent society, physical infrastructure and information technology are inseparable. The concept of cyber-physical systems (CPSs) is then proposed and has been widely concerned by researchers in recent years. Various models have been introduced to meet the actual needs. In one type of those models, the physical part and the cyber part are coupled and influence each other. The cyber part monitors and controls the physical part, but at the same time it may also bring certain harm; the fault in one part may also be transmitted to the other and affect the performance of the counterpart. Here, this paper introduces an asymmetric interdependent model and studies how the coupling pattern of CPSs affects the system robustness. In addition, the coupling pattern of CPSs is optimized by using the simulated annealing (SA) algorithm to reduce the performance loss. The results of this paper may find applications in the future CPS planning.