The invention provides a microelectronic phase-sensitive receiver, which has a simple structure, can accurately and reliably trigger a relay to work, and realize functions such as an abnormal alarm. In this microelectronic phase-sensitive receiver, the two sets of measurement circuits with MCU1 and MCU2 as the core have the same structure. The local voltage and track voltage are connected to the A / D input pin of the MCU through a micro-transformer, and the MCU collects two voltage waveforms in one cycle. , Calculate the initial phase angle and effective value of the two signals through the Fourier transform algorithm, find the phase difference, and make a logical judgment. When the conditions are met, output a square wave signal, which is amplified, isolated and transmitted, rectified and filtered, and output to be selected . MCU3 collects and calculates all four voltages, compares the results with the processing results of MCU1 and MCU2 to judge whether it is normal, selects one of them according to the set strategy, and outputs DC voltage through the output voltage terminal to make the 1700 relay work, if necessary Send an alarm signal.