The power quality analysis system is mainly used to analyze the AC voltage of 110kV and below in the medium scenarios of power grid and rail transit. It can record the waveform during the opening and closing process of circuit breaker or when the current and voltage are abnormal, and can read the current and voltage waveform in real time for power quality and waveform analysis. It has the functions of historical electrical data, real-time wave recording data, historical data copy, historical maximum data curve, historical power factor data curve, fault event recording, etc. The power quality analysis system has the characteristics of beautiful interface, simple operation, comprehensive display data and perfect analysis function. It is a ideal tool for on-line monitoring in communication.