The invention belongs to the field of electric energy meter monitoring, and particularly relates to an electric energy metering device online verification system comprising a data acquisition device, a data communication device, a data processing device, a PT acquisition device and a CT acquisition device which are arranged in a transformer substation, and preprocessing equipment, a management platform and a digital electric energy meter verification instrument which are arranged at a metering center. The data acquisition device and the data communication device are provided with a gateway meter interface. The data acquisition device is respectively connected with the data communication device and the data processing device. The data processing device, the PT acquisition device and the CT acquisition device are respectively connected with the data communication device. The data communication device is connected with the preprocessing equipment arranged at the metering center via a data network. The preprocessing equipment is respectively connected with the management platform and the digital electric energy meter verification instrument. The electric energy metering device online verification system is concise in structure and high in precision, and electric meter measurement equipment of the transformer substation is accurately monitored via front-end acquisition and rear-end acquisition so that loss can be reduced for users.