As wide area backup protection needs multipoint information to identify the fault element， high fault tolerance of the protection algorithm is the key to its correct operation. A novel wide area backup protection algorithm is presented based on wide area information fusion. Fault identification coding is formed according to the structure of the power grid， and the fitness and state expected function is constituted by the operation information of conventional main/backup protection and breaker status. Finally， the fault probability is calculated using the pre- and post-fault fitness function to realize the fault element identification algorithm. Simulation test based on IEEE 39-bus system demonstrates the effectiveness and excellent fault tolerance of this method.