The invention discloses a medium-and-long-time electric power load prediction method based on a fuzzy cluster, comprising steps of determining a prediction amount and an influence factor, obtaining sample data of various influence factors in a certain time frame through observation, establishing a fuzzy similarity relation of the sample data, analyzing the uniqueness, the similarity and the affinity degree of various samples, performing incorporation, classification and screening on the approximation sample, establishing a new behavior factor (load influence factor after clustering ) which is relatively independent and low in correlation, analyzing and calculating the gray absolute correlation degree and the weight coefficient of the sample sequence of the various sample sequences and the prediction quantity sequence (main behavior), fitting a data prediction value as an independent variable according to the sample clustering result and establishing a prediction model of a prediction quantity. The medium-and-long term electric power load prediction method based on fuzzy clustering is scientific, reasonable, easy to implement, accurate in prediction, strong in adaptability and applicable to the medium and long term power load prediction.