FlexRay, as a communication protocol for automotive control systems, is developed to fulfill the increasing demand on the electronic control units for implementing systems with higher safety and more comfort. Fault-tolerant feature is especially highlighted in the FlexRay protocol such that the FlexRay systems can be robust enough for applying to the safety-critical applications. In this work, we investigate the fault-tolerant mechanisms adopted in the FlexRay protocol, and propose an effective verification flow to justify the FlexRay communication robustness. The goal of the proposed flow is to ensure that the communication robustness can achieve the demanded safety integrity level (SIL) defined in IEC 61508 norm. Through a case study, the feasibility of the verification flow is demonstrated.