The invention discloses a hydropower station load interval prediction method. The historical load data is fully utilized, a similar day set of the day to be predicted is obtained by calculating the linear difference between the known moment load sequence of the day to be predicted and the actual load sequence of each historical day, the point predication is carried out on the day to-be-predicted according to the similar day of the day to be predicted, and then a large amount of historical load prediction error samples are analyzed to obtain a probability interval result of the possible valuesof the future loads. According to the interval prediction result, a hydropower station decision-making person can better recognize the uncertainty and the risk factors possibly existing in the futureloads during the production plan and the real-time scheduling, so that a more reasonable decision is made in time, and a basis is provided for the real-time load distribution of the hydropower station.