The five-phase fault-tolerant permanent magnet synchronous motor is introduced to meet the requirement of high reliability in the aero electric actuator. As the phase number of fault-tolerant motor increases, the fault types of fault-tolerant motor increase accordingly. As a prerequisite for fault-tolerant control, the requirements for fault detection and location accuracy are more stringent. Therefore, the state equation of five-phase fault-tolerant motor based on stator phase current is derived. On this basis, the fault-tolerant motor residual monitoring and model monitoring algorithm are proposed. The discretization implementation method of the monitoring algorithm is studied, and the effectiveness of the monitoring strategy is verified by simulation under different working condition.