The objective of this paper is to propose a new reliability analysis method for X-by-Wire systems, which includes both dynamic performance and static redundancy of the system. X- by-wire systems must meet not only reliability but also real-time requirements. In this context, we propose an integrated approach for evaluating both the performance in presence of perturbations - the Behavioural Reliability - and the evaluation of reliability based on classical failure rates of the components - the Static Reliability - of X-by-Wire systems. An example of quantification is given to illustrate the proposed method.