The utility model relates to a monitoring system for power quality monitor device passes through the electrical power quality data that the transformer substation was gathered to the data acquisition device, and the data transmission module will electrical power quality data transmits and stores in the data storage module of distal end, and data processing module follows again read among the data storage module electrical power quality data carries out power quality monitor device state analysis, therefore operating personnel need not to stop transport field device, also need not to go back to the dismouting of electric energy quality on -line monitoring device to the laboratory and detects to can improve improved electric energy quality on -line monitoring device operation status detecting's convenience, reduce cost. And improved electric energy quality on -line monitoring device reliability to the integrality and the exactness of improved electric energy quality data.