The invention discloses a building electricity consumption prediction method and system based on Stacking model fusion, and belongs to the field of building electricity consumption prediction. According to the method, multiple regression models are integrated by adopting a Stacking model fusion algorithm, an electricity consumption Stacking integrated model is constructed, the advantages of the multiple models are integrated, and prediction deviation is reduced; for buildings with unstable electricity consumption, the electricity consumption Stacking integrated model is trained by utilizing multiple influence factors such as historical electricity consumption, temperature, wind power, humidity and time information, so that the prediction accuracy is improved, managers of the buildings caneffectively control the energy consumption of the buildings, and the situation that the difference between the electricity consumption and the estimated electricity consumption is too large is avoided; according to the invention, reasonable estimation and purchase are carried out when a building manager participates in electricity market transaction, so that the building manager can effectively control electric charge expenditure, electricity selling arrangement of an electric power department or an electricity selling company is facilitated, the effects of energy conservation and emission reduction can be achieved, and good social benefits and economic benefits are achieved.