Aiming at the frequent faults of electric valves in nuclear power plants and the various types of faults, this paper analyzes the typical failure causes and fault information manifestations of electric valves by analyzing the structure and operation principle of electric valves, and studies the signal detection methods suitable for electric valve fault detection. Combining the data analysis and processing of various types of signals acquired, the electric valve signal processing and characteristic quantity analysis methods are proposed. By extracting the electric valve fault characteristic quantity, the fault state of the valve is further characterized. Combined with the actual valve operating state test, it is shown that the extracted characteristic quantities can reflect the true fault of the electric valve, which lays the technical foundation for the fault diagnosis and failure trend analysis of the electric valve.