Redundancy technique is an effective method to improve the ability of mission reliability, safety reliability and fault tolerant. With redundancy technique, it will increase additional system software and hardware resources, such as fault monitor module and channel switch module etc. In allusion to sensor fault, serial fault, controller fault and motor fault, this paper designs and researches the strategy of fault logic, fault management and fault reconstruction, appropriately distributes the system resources, thus effectively processes fault monitoring and isolating, and sufficiently improves mission reliability, safety reliability and fault tolerant ability of the dual-redundancy brushless direct current electric rudder loop.