Multi-functional electrical meter, an intelligent electrical meter with programmable measurement, display, RS485 digital communication, and electrical energy pulse output, capable of completing three-phase electrical parameter measurement (three-phase voltage, three-phase current, active power, reactive power, apparent power, power factor, frequency, etc.), harmonic measurement, grid quality analysis (voltage peak coefficient, current K coefficient, telephone waveform factor, voltage current unbalance degree, voltage current sequence quantity, etc.), four-quadrant energy metering, complex rate energy metering, maximum demand recording, SOE event recording, data display, collection, and transmission. Widely applicable in substation automation, distribution automation, intelligent buildings, and internal electrical measurement, management, and assessment in enterprises. Measurement accuracy of 0.5 class, with LCD on-site display and remote RS-485 digital interface communication, using standard DL/T 645-2007 or MODBUS-RTU communication protocol.