Tunnel Boring Machine (TBM) is a factorytype tunnelbuilding construction machine. Due to the numerous electrical facilities on the TBM, the highdegree automation and the complicated technology of the TBM, there are strict requirements for the safety protection of the electrical facilities on the TBM. This paper introduces several safety protection devices, such as TJB highvoltage cable couplers, highvoltage insulation, ground continuity monitor and insulation monitor.