The invention relates to the technical field of power, and especially relates to an electric energy quality monitoring system. The system comprises an electric energy quality monitoring terminal, a monitoring center main station, and a work station. The monitoring center main station and the electric energy quality monitoring terminal are connected with an electric energy quality monitoring management application system through network lines. The system can be used for building the electric energy quality monitoring management application system which accords with a power grid system building standard and is opened in a unified manner, so as to build a power grid electric energy quality monitoring, estimation, hazard analysis and measure management system netweork. Through the analysis and enhancement of power grid electric energy quality supervision and management, the system can guarantee the safe and stable operation of a power grid. Through the analysis of monitoring data, the summarizing of causes and the proposing of corresponding rectification measures, the system carries out the comprehensive treatment of electric energy quality, improves the power supply quality, reduces the equipment faults and power failure time, reduces the energy consumption, and provides advices for the optimization of the power grid and fault analysis.