The invention discloses a line loss analysis data reduction method based on an artificial neural network. Hour electric quantity curves of 24 hours of each day are classified through the artificial neural network; a feature curve of each curve is determined; the feature curves of the artificial neural network are subjected to mutation and leak data identification training, so that the feature curves have capacity of identifying mutation and leak data in the type of curves; and the mutation and leak data are precisely positioned through the artificial neutral network and then are finally reduced. Line loss analysis data of a power system are reduced by the artificial neutral network; and the problems of data efficiency, mutation and leak are solved.