The invention relates to a photovoltaic power plant data management system and a working method thereof. The photovoltaic power station data management system includes measurement and control devicesdistributed in each photovoltaic array, wherein each of the measurement and control devices respectively uploads the collected photovoltaic array data to a cloud server; and the cloud server is adapted to save the photovoltaic array data, and is suitable for downloading storage or online access through a management terminal. The photovoltaic power plant data management system provided by the invention is capable of collecting the photovoltaic array data, storing the collected photovoltaic array data in the management terminal, and then using the information backup subsystem to back up the photovoltaic array data, thereby ensuring the security of the photovoltaic array data.