We have self-developed on-line monitoring system for photovoltaic power station.The system is a set of intelligent monitoring system specially developed for photovoltaic power station and distributed photovoltaic power generation project, which integrates the functions of data acquisition, display, status monitoring, abnormal alarm and analysis. It can real-time monitor the operation conditions and coordinated control of core equipment such as photovoltaic array, inverter, combiner box and power distribution cabinet in photovoltaic power station, and meet the monitoring requirements of system safe operation and dispatching, and realize online real-time monitoring of multiple roof photovoltaic power stations in the workshops of its subsidiaries.