The invention discloses an output power classification forecasting system suitable for full life circle of a photovoltaic system. The output power classification forecasting system comprises a basic information storage module, a database module, a prediction model judgment module, a prediction data preprocessing module and a prediction modeling module. The system selects different prediction models to carry out training and predication according to data types and operation time of the photovoltaic system, is a modularized and multi-type photovoltaic system output power prediction system, can be suitable for output power prediction requirements of a majority of photovoltaic systems at present, can carry out customization according to the scale of the photovoltaic system and user requirements and the like, can both meet economic requirement and reliability requirement, and has good adaptability and transplantability. Meanwhile, the prediction method can update automatically; the prediction system can carry out automatic operation management; and higher prediction precision and stability are achieved.