In order to utilize the status information data of the relay protection device, improve the efficiency and quality of operation and maintenance, in this paper, the static historical data and real-time monitoring data of the relay protection device are mined and analyzed, and the reasonable monitoring parameters are selected to build the relay protection device status evaluation system composed of eleven evaluation indices. Then, the entropy method is used to conduct quantitative research on the weight of state evaluation index. According to the quantitative results, the grey correlation analysis theory is introduced to calculate the grey correlation degree between the real-time state and the optimal working state of the relay protection device, so as to realize the online analysis and real-time evaluation of its operating state, and provide technical support for the operation and maintenance of the relay protection. the static historical data and real-time monitoring data of nine relay protection devices in a substation are analyzed and studied, which verifies the reliability and accuracy of the state evaluation method.