Abstract: The control rod drive mechanism (CRDM) is the actuator of the reactor control and nuclear safety protection system. An important measure to prevent the occurrence of control rod stuck, sliding rod and driving failure in the reactor is to effectively monitor the operation status of the CRDM. Based on the analysis of the action principle of the control rod driving mechanism, this paper realizes the current monitoring and fault diagnosis of the control rod driving mechanism by studying the detection method, signal analysis and processing method and fault identification method of the driving mechanism, which lays a technical foundation for the application of the current monitoring and fault diagnosis system of the driving mechanism.