The invention discloses a system based on unit operation state real-time online monitoring. Online monitoring, data collection, data analysis, data processing, fault diagnosis and energy efficiency management of various data of a pump station are mainly studied. Data of all obtained state parameters is monitored according to the state, a feature value reflecting the unit operation state is extracted, the unit breaking down is diagnosed according to the feature value, and therefore the fault reason, portion, type, character, serious degree and development trend are determined, and maintenance is guided. According to energy efficiency management, the real-time data of all the obtained state parameters is monitored according to the state, efficiency calculation, economic indicators calculation and scheduling plan optimizing comparison are comprehensively carried out in combination with economic factors and market price factors of pump station operation, and therefore target optimization of energy efficiency management setting is achieved.