The invention discloses a BP neural network-based ultra-short load prediction method. The method includes the following steps of: step 1, microgrid load data identification and completion; step 2, microgrid load normalization processing; step 3, microgrid data de-noising processing; step 4, load sample difference calculation; step 5, RBF neural network load prediction mathematical model establishment and on-line prediction. According to the BP neural network-based ultra-short load prediction method, based on a traditional RBF neural network load prediction mathematical model, load sample difference is defined through a regression analysis method; and the prediction model is adjusted according to the load sample difference, so that the load prediction model can automatically adapt to load change.