The utility model provides a monitoring device, including electric energy quality monitoring circuit, input/output cell and the control unit, wherein electric energy quality monitoring circuit includes the signal acquisition and processing unit, keeps apart unit and data processing unit, the signal acquisition and processing unit is connected with the electric wire netting for, exports in the electric wire netting after gathering current signal, voltage signal and convert current signal, voltage signal into data signal, keep apart the unit, with the signal acquisition and processing unit connection for the data signal that will follow the receipt of signal acquisition and processing unit keeps apart the transform and exports after keeping apart the signal, the data processing unit is with the isolation unit connection for according to the isolation acquisition of signal electric energy mass parameter from keeping apart the unit receipt. Through setting up the isolation unit between signal processing unit and data processing unit, can realize forceful electric power system and light current system's isolation completely, avoided the impact to the device from the current signal of electric wire netting introduction and voltage signal, guaranteed forceful electric power system and light current system's electrical safety performance.