The online monitoring and condition evaluation system of electric power metering devices is an important part of the intelligent grid. It can reduce the maintenance workload of workers by timely and effective collection, monitoring and analysis of electric energy data and operation data of electric power metering devices, improve the lean degree of operation management of metering devices in electric power enterprises, and enable power supply enterprises to timely master the use of electric energy and the quality of grid operation. Therefore, this paper designs the condition monitoring system (CMS) of gateway metering device (GMD) based on genetic algorithm (GA). This paper discusses the status monitoring design of GMD and the abnormal monitoring of metering device, and analyzes the application of GA in the design of GMD status monitoring system; Through the realization and application analysis of the online monitoring and status evaluation system for GMDs, the operation data and operation status data of metering devices are obtained dynamically and in real time, which not only ensures the safety of the operation of metering devices, but also greatly reduces the workload of management, operation and maintenance, and greatly improves the efficiency of management and maintenance.