In order to improve the efficiency of maintenance of electronic watt-hour meter, the paper puts forward a design scheme of remote on-line detection system for electronic watt-hour meter based on instrumentation and measurement cloud. Under the control of the master station, the system can acquire the voltage and current data through the field data collection terminal, and process the measured data through the instrumentation and measurement cloud platform. The system realizes remote online detection with on-site data acquisition, cloud processing and remote interactive. It has the advantages of easy deployment and maintenance, low cost, and can be used in harmonic analysis, fault diagnosis and other fields.