In this study, a method for evaluating the failure probabilities of bridge systems and members based on a time-variant system reliability theory and a method for evaluating the failure probabilities of bridge systems and damage probabilities of members based on Markov chain were proposed. And the safety of RC bridge systems which are consisted of aseismic base isolation shoe, RC pier, and pile against earthquake is evaluated on the basis of the proposed method. Furthermore, the influences of member failure on the safety of bridge systems under earthquake are examined by use of the proposed method.